Philippart, Frank (2008). "The Cointet element"(PDF). Workgroup Modern Fortifications News (3): 1–7. Archived from the original(PDF) on 18 May 2014. Retrieved 8 January 2012.
Philippart, Frank (2008). "The Cointet element"(PDF). Workgroup Modern Fortifications News (3): 1–7. Archived from the original(PDF) on 18 May 2014. Retrieved 8 January 2012.