T.  Ohba and Kimura, Y., ?Hypericum mutilum L., naturalized in Chiba Prefecture, Japan.?, J. Jap. Bot., vol. 75, pp. 316-318 (2000) - col. illus., 2000.

F.  Kuginuki and Namba, T., ?Pharmacognostical studies on the folk medicine in Japan: 10. On "Otogiri-so". Anatomical features of leaves and stems of  Hypericum and Triadenum (Hypericaceae): 1.?, J. Jap. Bot., vol. 68, pp. 224-235 (1993) - illus., 1993.

F.  Kuginuki and Namba, T., ?Pharmacognostical studies on the folk medicine in Japan: 13. On "Otogiri-so". Anatomical features of leaves and stems of genus Hypericum (Hypericaceae): 2.?, J. Jap. Bot., vol. 68, pp. 261-273 (1993) - illus., 1993.

Y.  Kimura, ?The type specimen of Hypericum japonicum Thunberg.?, J. Jap. Bot., vol. 55, pp. 81 - 85 (1980)   illus., 1980.

N. K. B.  Robson, ?Notes on some Nepalese and Indian Hypericum.?, J. Jap. Bot., vol. 52, pp. 276 - 288 (1977) -   maps, keys., 1977.