Geil, William Edgar. The Great Wall of China,. New York: Sturgis & Walton, 1909. Print.
"Great Wall of China, History, Gallery of Pictures, Travel Guide, News, Discovery & Research." Great Wall of China, History, Gallery of Pictures, Travel Guide, News, Discovery & Research.
Hinago, Motoo, and William Howard. Coaldrake. Japanese Castles. Tokyo: Kodansha International and Shibundo, 1986. Print.
Hirai, Kiyoshi. Feudal Architecture of Japan. New York: Weatherhill, 1973. Print.
Man, John. The Great Wall: [the Extraordinary Story of China's Wonder of the World]. Cambridge, MA: Da Capo, 2008. Print.
Ōrui, Noburu, and M. Toba. Castles in Japan. [Tokyo]: Board of Tourist Industry, Japanese Government Railways, 1935. Print.
Turnbull, Stephen R. Strongholds of the Samurai: Japanese Castles 250-1877. Oxford: Osprey, 2009. Print.
Waldron, Arthur. The Great Wall of China: From History to Myth. Cambridge [England: Cambridge UP, 1990. Print.