[1]Art of the samurai: Japanese arms and armor, 1156–1868, Authors Morihiro Ogawa, Kazutoshi Harada, Publisher Metropolitan Museum of Art, 2009, ISBN1-58839-345-3, ISBN978-1-58839-345-6 P.193
[2]The Japanese sword,Kanzan Satō, Kodansha International, May 30, 1983 P.196
[3]Samurai: The Weapons and Spirit of the Japanese Warrior, Clive Sinclaire, Globe Pequot, Nov 1, 2004 P.88