Tokoro Isao, Kure Asao, Goshima Kuniharu, Yoshino Ken'ichi, Hashimoto Tomitarō = An account of the creation of the names for imperial eras in Japan : explaining the selection of names given to the 247 imperial eras from Taika (645) to Heisei (1989) / editor, Tokoro, Isao ; contributors, Kure, Asao, Goshima, Kuniharu, Yoshino, Kenichi, Hashimoto, Tomitaro