For the difference between bunkers and blockhouses see Schneider & Kitchen 2002, halaman 87, BACM Research 2009, halaman 263, Davis 2007, halaman 290 Schneider, Richard Harold; Kitchen, Ted (2002), Planning for crime prevention: a transatlantic perspective, RTPI library series, 3 (ed. illustrated), Routledge, m/s. 87, ISBN978-0-415-24136-6 Davis, Tracy C. (2007), Stages of emergency: Cold War nuclear civil defense (ed. illustrated), Duke University Press, m/s. 290, ISBN978-0-8223-3970-0
