1. Bradlow, H.L. (1968). Steroids11, 265
2. Fieser, L.F., Fieser, M. (1959). Steroids, p.504. New York: Reinhold Publ. Corp.
3. Fimognari, G.M., Rodwell, V.W. (1965). Biochemistry4, 2086
4. Kozlova, V.K., Fonina, N.A. (1972). Mikrobiologiya41, 602
5. Lee, S.S. (1967). Seoul Univ. J (c)18, 94