E-Book Technology and Its Potential Applications in Distance Education
AbstractThe potential for distance learning students to use e-books is explored. E-books are gaining wider interest since the introduction of portable electronic reading devices and software-based readers that provide users with more realistic book reading experiences. The paper discusses where to acquire e-book technology, and how to create e-books. It also reports an evaluation to test the usability of different types of e-book compiler software. By using one of the compilers, the use of e-books to improve the interaction between educators and distance learning students in terms of access to teaching and learning materials and submission of assignments is also demonstrated.
There is a growing interest in converting paper books to bytes (Carvajal 1999) as well as writing new titles in digital form. This in turn has resulted in a collection of hybrid definitions of e-books. Initially, paper books that had been converted to a digital format, usually through digitising processes which allow them to be displayed on computers, were defined as e-books. Then, the term also began to encompass multimedia, hypertext or hypermedia systems that are based on a book metaphor. Recently, the definition of an e-book has been extended to include book titles that are available online, that can be read as email, can be retrieved by a portable electronic reading device, or as a file that can be downloaded on to a computer (Carvajal 1999, Allen 2000, Clister 1999). Another recent interpretation of an e-book is the "print-on-demand" book where the contents are stored in a system connected to a high-speed, high-quality printer, from which printed and bound copies are produced on demand with the possibility of buying chapter-by-chapter, customised books (Hawkins 2000a).
E-books are also defined diversely by researchers to fit their own expectations. For example:
- any kind of digitised information ranging from a CD-ROM title to an online interactive database or a collection of Web pages;
- a collection of reactive pages of electronic information that exhibit many of the characteristic features and properties of a conventional book;
- learning environments which have an application containing a multimedia database of instructional resources that store pre-captured multimedia presentations about topics in a book.
The Open eBook (OEB) Forum avoids using the term e-book because different people use the term differently. OEB defines a more precise terminology:
- the digital content which users read (i.e. a paperless version of a book, article, magazine, etc.) is called publication;
- the physical device used to read a publication is called a reading device (e.g. dedicated readers (see section 2), personal computers or personal digital assistants);
- the combination of software and hardware that processes content and presents it to users is called a reading system.
This paper starts with discussion of hardware and software based e-book readers. Different types of e-book formats and standards are detailed. This is followed by a discussion on electronic publishers (e-publishers), electronic bookstores (e-bookstores) and digital libraries where e-books can be acquired and purchased. The publishing process and how to build e-books using e-book compilers are explained. The final part of this paper highlights the use of e-books to improve the interaction between distance learning students and educators, and to improve access to learning materials.
At present, delivery of e-books through CD-ROM and the Internet is the most popular mode. In 1998 another type of e-book medium was introduced to the public: dedicated readers or hand-held devices and/or slates. The emergence of the e-book has resulted in many companies manufacturing electronic reading devices (dedicated readers) used for displaying, reading and storing electronic information. NuvoMedia Inc., SoftBook Press Inc., EveryBook Inc. and Sony (Sanders and Sanders 2000) are examples of manufacturers of such devices. Gemstar International Group, one of the leading companies involved in electronic technology, acquired NuvoMedia and SoftBook Press in early 2000.
The nature of the devices market has been evolving. Initially the companies only targeted professionals who require access to lots of reference material (Judge 1998). Now, they are targeting a more general mass market such as students, academics and individuals. These machines are produced purposely for reading downloaded electronic contents. They are lightweight devices aimed at duplicating the familiar experience of reading a paper book, yet contain electronic-age features to further enhance convenience and enjoyment (Thomson Multimedia 2000). Examples include:
- NuvoMedia Rocket eBook (now obsolete);
- RCA REB 1100 and 1200 (Figure 1);
- Microsoft IPM-NET Myfriend
- Cytale Cybook
O'Donnell (1998) stated that all these devices have one common function in that they are dedicated to reading e-books only, and are not as sophisticated as handheld computers or personal digital assistants (PDAs). This statement no longer holds, however, as since 2000 hybrid devices (Wilson 2001) that contain address books, diary, calculator and PDA-associated functions have also been used to read e-books. Additionally, these devices can be used for emailing, Internet surfing, word processing and playing MP3s. An example is the Franklin eBookMan.
The latest addition to PDA technology is the all-in-one colour monitor handheld O2 xda which allows users to access the Internet, make phone calls, send emails, use Microsoft Word and Excel, read e-books, organise a diary, listen to music and play games. PDAs are rapidly becoming a common technology at school because they allow students and teachers to do essential tasks such as note taking, word processing, graph drawing, emailing and browsing. The ReBookTM from RealTimeTouch.com will allow print, video, audio, interactive touch and wireless communications.
Another approach, demonstrated by the EInk project, is a flexible paper-like electronic display on thin sheets of plastic. The basic idea behind electronic paper is that it is a reusable display device, allowing storage of visual content on a 'page' of plastic paper. This technology is in its very early stages, but EInk has expressed the desire to create the technology to allow the development of electronic devices that work like paper books.
Nuvomedia, SoftBook Press and EveryBook were the pioneers in terms of introducing reading devices (Manes 1999). They have a number of advantages and disadvantages. Some of the advantages over traditional paper books include:
- they can store tens to hundreds of titles, making them ideal for convenient, portable access to reading material from virtually any location (Thomson Multimedia 2000);
- they incorporate features such as interactive dictionaries, bookmarking, instant searching, note taking and cross referencing;
- the back-lit display and font size can be adjusted to improve readability (Selvidge and Phillips 2000).
Full descriptions of the advantages of these reading devices can be found in Williams (2000a). Although they have a number of advantages over paper books, reading from these devices is reported to cause more eye strain and glare (Williams 2000b). Display quality is poor (because of low resolution) compared with paper, and the devices are still too expensive for the average person to buy.
In addition to e-book reading devices, general-purpose software book readers can be used on personal computers or laptops. These function in similar way to dedicated readers but no special hardware is required. Microsoft Reader, Adobe Acrobat Reader and Adobe Acrobat eBook Reader are three examples of such software. One advantage of software-based readers (Lynch 2001) is that in addition to offering the functions of dedicated readers, they offer extra facilities through a keyboard and larger screen size.
Two versions of the Microsoft Reader are available as a free download from the Microsoft Web site:
- for desktop and laptop computers - can read encrypted e-books, such as those available at BarnesandNoble.com and Amazon.com, as well as unencrypted e-books usually found at electronic publisher Web sites;
- for Pocket PC devices - reads only unencrypted e-books.
The Microsoft Reader interface is designed specifically for reading online. It includes ClearType technology developed by Microsoft to enhance LCD screen clarity, and allows annotation, bookmarking, drawing and font size alteration. A text-to-speech feature can be activated when the associated software is downloaded from Microsoft. However, it supports only a one-page view (see Figure 2) compared with Adobe Acrobat eBook Reader.
Acrobat ReaderTM is freely downloadable software that allows users to read Portable Document Format (PDF) files. Acrobat Reader is widely used and comes pre-installed on many computers, making PDF a popular e-book format.
Glassbook Reader was recently renamed Adobe Acrobat eBook Reader and is a freely downloadable program that enables users to read PDF-based e-books on laptops, notebooks or desktop PCs. It allows easy buying and downloading of e-books at the Adobe eBook Mall and other online booksellers such as eBookTech.com, McGraw-Hill Primis Online, Taylor & Francis eBookstore, Harcourt College Publishers, CyberRead.com and BarnesandNoble.com. Features include (Figures 3 and 4):
- single and two-page display to emulate the traditional reading experience;
- integrated bookstore access and downloading of e-books into a personalised library;
- bookmark, highlight, annotation and search tools that make it easy to locate specific passages;
- rotating display and controls (i.e. able to change page orientation) for use on notebook computers;
- access to Web links contained in e-books;
- high-fidelity, full-colour display of e-book pages.
E-books are available in a wide range of formats, the simplest of which is plain ASCII-standard text. However, this format is extremely unappealing to read, cannot preserve formatting and cannot handle graphics. To solve these problems, the following formats can be used (Allen 2000, Armstrong and Lonsdale 1998, Hawkins 2000a):
- Adobe Acrobat's Portable Document Format (PDF) ;
- Microsoft Reader's Literature (LIT) ;
- Rich Text Format (RTF);
- Night Kitchen's Tool Kit 3 (TK3) ;
- Markup Language (e.g. HyperText Markup Language - HTML, Standard Generalised Markup Language - SGML, eXtensible Markup Language - XML);
- Software for PDAs such as AportisDoc for Palm Pilots and Pocketbooks, Palm Reader and Mobi-Reader for Palm Handheld, Handspring Visor, and Window CE devices.
The most popular journal formats according to Hitchcock et al. (1997) are either HTML or PDF. Although that study is now rather dated, the findings hold for existing e-books considered in this study. This may soon change as the LIT format is becoming widely used.
Although a single standard for e-book formats does not yet exist (as at the end of May 2002), NuvoMedia and SoftBook Press co-developed and proposed the Open eBook Publication Structure (OEBPS) in 1999. OEBPS is based on HTML and XML specifications for the content, structure and presentation of e-books, and is supported by more than 200 companies including IBM, Microsoft and Adobe (Thomson Multimedia 2000, Hawkins 2000b). Although Adobe is one of the members of OEB Forum, the company is actively pushing its PDF format to be the de facto e-book standard. Microsoft, on the other hand is in favour of HTML and Word documents, and has developed LIT which supports OEBPS. Frauenfelder (2000) described and compared the features of these formats, concluding that publishers would prefer the de facto standard to be OEBPS or PDF.
Content for the readers can come from a variety of online sources such as novels, journals, newspapers, magazines and manuals. Unfortunately the number of printed books, especially textbooks, in electronic format is relatively small. Online books currently consist mostly of works whose copyrights have expired (Moschella 1999). Project Gutenberg has been collecting thousands of out-of-copyright titles since 1971 and offering them to the public for free. A new trend is emerging, however, where electronic publishers such as Fatbrain, iUniverse and IstBooks have successfully produced and sold new electronic titles. Customers have shown an interest in books about computers and business (Carvajal 2000) as well as romance and science fiction novels (Allen 2000, Hawkins 2000a ). Well known writers such as Stephen King are among those interested in marketing their books in electronic format. To buy textbooks using "print-on-demand" or custom-made chapters and pages, readers can go to McGraw Hill Primis. This is an innovative bookselling concept that allows readers to buy e-books which are read using software-based readers such as Adobe Acrobat eBook Reader.
OZONeBOOKS.COM, Atlantic Bridge Publishing, BOOKS ONSCREEN, Ebook Express, EBook Mall and Hypertech Media Inc, VanGoach Books, Bookmice, DiskUs Publishing, Ebook On the Net, Book Locker, Zorba Press, Fiction Works, eBooks N' Bytes, Powells.com, Barnes & Noble and Bookface are other examples of popular publishers and bookstores.
Books that are produced and stored electronically rather than in print are the result of electronic publishing (e-publishing). From a financial point of view, e-publishing eliminates printing, binding, storage and transportation costs (Borchers 1999). Nevertheless, it is probably just as costly (or more costly) to employ skilled editorial and technical staff (such as graphic artists, audio and video specialists, animators, etc.) to prepare data for electronic publication as it is for paper based publication.
As there is still no single standard format, or indeed a universal definition, for an e-book, the process of producing one can still be interpreted in many different ways depending on the type of e-book and its purpose. For example, for textual e-books, the process can involve simply digitising a printed book, or applying markup languages. For multimedia or hypermedia books, a different approach is often required, involving additional steps such as creating graphics, audio, animation and video.
The e-book publishing industry is currently concentrating on textual e-books with limited multimedia content (van Buren and Cogswell 2001). The e-publishing process closely resembles traditional print publishing (Modeland 2000, Prabha 2000) and goes through similar stages:
- Manuscripts are evaluated (for new books) or acquired (if paper versions exist);
- If a book is marketable, contracts are signed;
- Content editors edit the manuscript for quality;
- Manuscripts are proof-read;
- Final edited manuscripts are processed (i.e. e-books are created) and saved in various formats, as described earlier. This involves a further four sub-steps: planning, designing, creating and testing;
- Book is stored and delivered on suitable medium.
In the e-publishing process, stage 5 entails further phases, which are adopted from the software development life cycle (see books on software engineering) to provide the e-books with an appropriate user interface and content presentation. The phases involved in stage 5 depend greatly on the type of content to be produced and their purposes. The contents can be in any of the following form:
- any one medium (for example fully textual, graphics-only content, or audio-only content);
- multimedia or hypermedia (i.e. mixing more than two media).
According to Borchers (1999) each category can be used in education (e.g. textbooks), for reference (e.g. dictionaries), leisure (e.g. novels, comics), browsing (e.g. newspapers) and advertisements (e.g. brochures). If an e-book is being produced for learning purposes, its development process should also consider instructional design (a systematic approach to designing instructional materials to achieve specified learning objectives; Bostock 1998) and accommodate a wide range of different learning styles.
One good example in creating textual e-book content is to follow the phases suggested by Landoni (1997). She started by selecting a formalism (either logic or grammar) then constructed a conceptual model, which defines the structure of the e-book. Then the interface was designed with specific attention paid to ergonomic and text presentation issues.
Creating textual e-books is becoming easier with the introduction of e-book compilers. Books are created by merging the existing text files, and the compilers automatically generate the structure and the interface of the books. Designing multimedia or hypermedia books normally requires more steps as it involves more media. In textual e-books (or any other single medium), designers need only follow guidelines such as using appropriate fonts, making text readable and considering type styles and colours. For multimedia or hypermedia books, on the other hand, design considerations are focused on graphics, audio, animation, video, text, as well as on their combination.
There are a number of resources that give advice and guidelines for authors who are interested in publishing e-books. A typical example is Writing-World.com. Among the popular publishers and e-book stores are: OzoneBooks.com, Atlantic Bridge Publishing, Artemis Press, Bogsidebooks.com, Books Onscreen, BookZone, Crystal Star Publishing, Ebook Express and eBook Mall.
Some publishers require submissions to follow certain guidelines to ensure easy conversion to their e-book format, e.g. for e-books to be read using Microsoft Reader, some publishers ask for the following:
- files must be in plain ASCII (.txt) format;
- manuscripts must consist only of these characters A - Z, 0 - 9, " = : ? £ $ % & ( ) - + @ ! , .
- manuscripts must be divided into chapters, and saved as a separate file for each chapter;
- each chapter must be numbered in sequence, and the chapter number must be included on the first line;
- manuscripts must be unformatted;
- image size is not larger than 510x680 pixels, and of format .JPG or .GIF only.
Authors have three e-publishing choices: commercial, subsidy (vanity) and self-publishing (Henke 2001). Commercially published e-books are sold primarily through the publisher's Web site and online bookstores. Authors pay no publication fee, and receive royalties. Subsidy e-publishers produce and distribute books for a fee, and authors receive royalties. Unlike commercial books, manuscripts for subsidy books are usually accepted regardless of their quality, and publishers do not provide editorial services or proof-reading, and the responsibility for promoting a book rests primarily with the authors (Henke 2001, Allen 2000). In self-publishing, the authors are responsible for the entire process of publishing their books, from development to marketing. A more detailed information about these publishing choices is discussed in Henke (2001) and van Buren and Cogswell (2001).
Contents which have been developed and saved as HTML, text pages or sometimes PDF formats can be turned into a single executable file. This is achieved through the use of a program called an e-book compiler. A compiler can be defined as software that is designed to take a number of HTML or text pages and combine them into a single file. There are numerous compilers on the market:
- EBook Edit Pro
- Activ EBook
- HyperMaker HTML
- HTML Compiler Pro
- Illuminatus v4.51
- Ebook Creator
- ebook Generator
For students or individuals who cannot afford to buy commercial compilers, there are also free and trial compilers that can be downloaded from the Internet (e.g. Ebook Builder 4 and KeeBook Creator).
Microsoft has also developed its own compiler, ReaderWorks, which supports Microsoft Word, documents, text and HTML files, and the finished products are read using Microsoft Reader. Other tools that can be used to build e-books for Microsoft Reader include Microsoft Reader add-in for Microsoft Word 2000, Microsoft Reader Content SDK, and Mobipocket Publisher. To create PDF files, users can use Gymnast, freeware by Robert Schifreen, which supports hyperlinks, annotations, and automatic generation of bookmarks from headings.
Each compiler has its own set of features. Some have more features than others, some have similar features and some have unique features. Most e-book readers, for example, either hardware or software based, provide a personalised digital library where a collection of books is stored. Almeida (2001) reviews most of the compilers listed above.
To test the ease of use of some e-book compilers, the book Usability in Political Web Sites was created using three different compilers: Keebook Creator Version 2.6, Gymnast, and Microsoft ReaderWorks. The content of the book is about usability issues to be considered by designers of political Web sites, which can be defined as sites normally classified into political parties, non-profit organisations, government agencies, pressure groups, or even individuals. Such sites aim to disseminate political information and invite people to get involved in discussions about social and public issues. The book has four chapters:
- Web Sites: Some Definitions
- Concept of Web Usability
- Factors Affecting Web Usability
- Usability Issues in Political Web Sites: Users' Perspectives
The content of the book was first written in Microsoft Word in four different document files. All the compilers were downloaded from the Internet and installed in a personal computer. Each compiler was opened to test whether it was in working order. Before using the software, the instructions on how to use the software were studied. The book was then developed using all the three compilers. The development time and some screenshots were taken during each development for comparison.
In general, Gymnast is an effective and easy-to-use program that allows users to convert any text document files into PDF . When the program is launched, a form is opened where users can start the file conversion process (Figure 5). The layout of the form is fairly simple and easy to understand, and it requires users to fill in some information regarding the document to be converted, which includes source files, document information, and page properties. Once finished, users can convert the file by choosing the conversion option in the 'File' pull-down menu. To read the book, users have to launch the Acrobat eBook Reader. In our study, the document files used were successfully converted although some tables and figures appeared to be missing.
Unlike Gymnast, Keebook Creator allows users to build books and view them within the same environment (Figure 6). When the program is launched, users are prompted with option to open an existing or a new project. If users opt for a new project, a dialogue wizard box is opened where users can provide information on the book title, author, and where to locate the book in the library book. Then users can start building books by creating chapters, inserting the source document files into chapters, and editing the table of contents. In our study, the book was successfully created (see Figure 6) without major problems. The only concern was that any file imported was converted into one long page, making readers scroll down to read a particular chapter. This software is unable to convert the document file into its original page-by-page format as Gymnast does. Nonetheless, the software has a usable interface with features that are easy to use and understand. It allows users to build books in several viewing modes including library mode.
Building e-books in ReaderWorks is slightly easier than Gymnast and Keebook. Its interface is more professional and the menu is based on the step-by-step process of building a book as normally executed by authors (Figure 7). Using this software, users can easily add source files, define book properties, insert a table of contents, design the cover page and, most importantly, define the navigation system within the book. Compared to the previous two compilers, users can add more information in the book properties, for example, descriptions, co-authors, publisher, date, type, and copyright statement.
From this evaluation, we concluded that the best reader and compiler for inexperienced writers are Microsoft products (i.e. Microsoft ReaderWorks and Reader). This result informed an experiment to demonstrate how e-books can enhance interaction in distance education, as discussed in the next section.
E-books have potential in enhancing distance education. In particular, e-books are able to enhance the interaction between educators and students when dealing with teaching and learning materials. To demonstrate this idea, we used a remote testing approach and asked a group of students (representative users) who had no prior e-book reading and building experience to submit assignments (typical students tasks) in LIT format. Remote testing is used when researchers are separated in space and/or time from the participants. This means that the researchers cannot observe the testing process directly and that the participants are usually not in a formal usability laboratory. On completion of the tasks, the participants were asked to describe their experiences in written form.
The task instructions were delivered with a set of lecture notes, which was also in LIT format. Students were instructed to download Microsoft Reader into their personal computers and read the lecture notes containing information on how to use Microsoft Reader, the assignments, how to build an e-book from their completed assignments and how to submit it to the lecturer. They were also asked to treat the notes as if they were reading a printed version. The completed assignments were read and marked by the lecturer using Microsoft Reader as well. The annotating, drawing and highlighting features in the reader were used extensively by the lecturer. Marked assignments containing the lecturer's annotations and comments were sent back to the students. At the end of the experiment, their experiences were noted, paying particular attention to positive and negative comments.
- Improves on-screen reading experience when compared to lecture notes sent in word processor format or slide presentation or Web pages.
- The possibility of imitating actions used on printed notes, such as highlighting, bookmarking and annotating, is seen as very useful and helpful.
- Accessing links from within the notes is very useful.
- Compiling an assignment in an e-book format, with a cover and table of contents, improves presentation.
- Students could store their collections of assignments (in the e-book form) in the personalised digital library provided in the reader, thus saving physical space as well as increasing the portability.
- By the end of their course, many e-books would have been created, thus improving the electronic authoring experience and promoting self-publishing.
- Lecturers' comments (in digitised hand writing form and attached notes) included in the marked assignment give students a "sense of the lecturer's personal touch" on their work. In addition, students could read and identify the strengths and weaknesses of their work, from the lecturer's point of view. This "personalised" touch is one of the traditional interaction methods in the education environment, but is either difficult or not possible in other submission-return methods for electronic assignments.
- Lecturers' responses and comments on students' work are delivered faster via the Internet.
- Even though multimedia capabilities are not considered crucial to adult learners, the need is there, especially when complex concepts are to be explained in distance education. Currently, e-book technology (i.e. either hardware or software based readers) has limited multimedia features. To overcome this now, educators could include external links or simply attach email files to the students.
- Reading online is still not as comfortable as printed notes.
- The portability of software-based readers is not as good as for hardware readers, but hardware-based readers are still too expensive for students.
The students were asked whether they are interested in using e-book technology in their course, and whether they are interested in reading books online (i.e. using computers or handheld device monitors). Figures 8 and 9 present their responses.
Figure 10 summarises the potential of e-books in enhancing educator-student interaction.
Current developments in e-book technology have been described and the results of two experiments reported. The primary aim of the experiments was to explore the potential for using e-books in supporting distance education. It is inappropriate to generalise the findings as only 11 students participated in the experiments, but it has been demonstrated that e-books have potential in enhancing educator-student interaction. The findings also show that students are interested in using e-book technology. It is suggested that more studies using larger samples should be directed at exploring the potential, effect and impact of e-books in distance education.
Allen, M. (2000) "E-Publishing FAQ".
Almeida, E. (2001)
eBooksN'Bytes Software Review. eBooksN'Bytes
Armstrong, C. and
Lonsdale, R. (1998) The Publishing of Electronic
Scholarly Monographs and Textbooks
Borchers, J.O. (1999) "Electronic Books: Definition, Genres, Interaction Design Patterns". Conference on Human Factors in Computing Systems, CHI99 Workshop: Designing Electronic Books, Pittsburgh, May
Bostock, S. (1998)
Courseware Engineering - an overview of the courseware
development process. University of Keele
Carvajal, D. (2000) "Digital Publishing: From Arthur C. Clarke to Psoriasis Tales". The New York Times, February 7th
Clister, J. (1999)
"Electronic Books". Conference on Human Factors in
Computing Systems, CHI99 Workshop: Designing Electronic
Frauenfelder, M. (2000) "Digital Publishing: An Open E-Book?" The Industry Standard, August 7th http://www.thestandard.com/article/display/0,1151,17188,00.html
Hawkins, D. (2000b) "Electronic Books: A Major Publishing Revolution, Part 2". Online, 19-35
Hitchcock, S., Carr,
L. and Hall, W. (1997) "Web Journals Publishing: A UK
Perspective". Serials, 10(3), 285-299
Judge, P. (1998) "E-books: A library on your lap". BusinessWeek, November 5th http://www.businessweek.com/1998/46/b3604010.htm
Lynch, C. (2001) "The Battle to Define the Future of the Book in the Digital World". First Monday, 6(6), June http://www.firstmonday.org/issues/issues/issue6_6/lynch/index.html
Moschella, D. (1999)
"Electronic books are poised to become a key medium".
CNN, April 23rd
O'Donnell, B. (1998) "Is the world ready for digital books?" Info World Media Group Inc., July 6th http://www.everythingcomputers.com/1998%20Columns/July/july_6_1998_column.htm
Prabha, C. (2000)
"Understanding the elements of book publishing". OCLC
http://www.oclc.org/oclc/new/n229/research.html (scroll down page)
Schilit, B. (1999) "Why
e-Read? Finding opportunities in the merger of paper and
computer". The Future of Print Media, Spring
Selvidge, P. and
Phillips, C. (2000) "E-books: Are We Going Paperless?"
Usability News, Usability Research Laboratory,
Wichita State University
Stork, P. P. (2000) "The Promise of eBook Publishing". The Internet Writing Journal (IWJ), 4(9) http://www.writerswrite.com/journal/oct00/stork.htm
Williams, G. (2000b) "A Few Things that Absolutely Must Change in the eBook Industry". eBook-Net.com
Wilson, R. (2001) "Evolution
of Portable Electronic Books". Ariadne, issue