Crane 2012, p. 2; Saunders 1989, p. 42; "East Blockhouse, Angle (103035)", Coflein, RCAHMW, retrieved 10 May 2015 Crane, P. (2012). East Blockhouse, Angle: Archaeological Excavation, July 2011. Carmarthan, UK: Dyfed Archaeological Trust. Saunders, Andrew (1989). Fortress Britain: Artillery Fortifications in the British Isles and Ireland. Liphook, UK: Beaufort. ISBN1855120003.
Harrington 2007, p. 11; Walton 2010, p. 70 Harrington, Peter (2007). The Castles of Henry VIII. Oxford, UK: Osprey Publishing. ISBN9781472803801. Walton, Steven A. (2010). "State Building Through Building for the State: Foreign and Domestic Expertise in Tudor Fortification". Osiris. 25 (1): 66–84. doi:10.1086/657263. S2CID144384757.
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Harrington 2007, p. 11; Walton 2010, p. 70 Harrington, Peter (2007). The Castles of Henry VIII. Oxford, UK: Osprey Publishing. ISBN9781472803801. Walton, Steven A. (2010). "State Building Through Building for the State: Foreign and Domestic Expertise in Tudor Fortification". Osiris. 25 (1): 66–84. doi:10.1086/657263. S2CID144384757.