^Brown, Delmer Myers; Hall, John Whitney; Shively, Donald H.; McCullough, William H.; Jansen, Marius B.; Yamamura, Kōzō; Duus, Peter, eds. (1988). The Cambridge History of Japan, Volume 2. Vol. 2 of The Cambridge History of Japan: Heian Japan. 耕造·山村 (illustrated, reprint ed.). Cambridge University Press. p. 95. ISBN0521223539.
^Brown, Delmer Myers; Hall, John Whitney; Shively, Donald H.; McCullough, William H.; Jansen, Marius B.; Yamamura, Kōzō; Duus, Peter, eds. (1988). The Cambridge History of Japan, Volume 2. Vol. 2 of The Cambridge History of Japan: Heian Japan. 耕造·山村 (illustrated, reprint ed.). Cambridge University Press. p. xxi. ISBN0521223539.