1. 1) “Kajuengei Daihyakka 6” [Encyclopedia of Orcharding Vol. 6], Nôbunkyô, Nôsan Gyoson Bunkakyôkai, Tokyo, p. 109 (2000).
2. 2) “Saishin Engei Daijiten 3” [Encyclopedia of horticulture Vol. 3], Saishin Engei Daijiten Henshû Iinkai, Seibundou Shinkôsha, Tokyo, p. 1258 (1969).