1. Bryant, A.T., 1983. Zulu Medicine and Medicine Men. Centaur Press, Cape Town, pp. 61.
2. Drewes, S.E., 1974. Chroman and Related Compounds. Verlag Chemie, Weinheim, p. 49.
3. Management of erectile dysfunction by the geriatrician;Godschalk;Journal of the American Geriatrics Society,1997
4. Hutchings, A., 1996. Zulu Medicinal Plants. University of Natal Press, Pietermaritzburg, South Africa, p. 145.