E. H.  Walker, Flora of Okinawa and the southern Ryukyu Islands. Washington, D.C.: Smithonian Institution Press, 1976.

S.  Hatusima, ?Two new species of Burmanniaceae from Japan?, Journal of Geobotany, vol. 24, pp. 2 - 10, 1976.

M. R.  Mesler, ?Gametophytes and young sporophytes of Ophioglossum crotalophoroides Walt.?, Amer. J. Bot., vol. 63, pp. 443 - 448, 1976.