Donnelly, James, Pieter Bakker, Bas Reedijk, and Yang Zi Qian. “XBLOC-PLUS: THE INTERLOCKING, PATTERN PLACED AND EFFICIENT ARMOUR UNIT”. Coastal Engineering Proceedings, no. 36v (December 28, 2020): structures.18. Accessed January 28, 2022. https://journals.tdl.org/icce/index.php/icce/article/view/10165.