1997 IUCN red list of threatened plants (1997)

The botanical magazine = Shokubutsugaku zasshi - Nihon Shokubutsu Gakkai. (Tokyo Botanical Society, 1919)

ri ben zhi wu ming hui - Honda, Masaji 本田正次 1897 -1984 (san sheng tang)

The World List of Threatened Trees (1998)