1. Murray, H.C. and Peterson, D.H., US Patent No. 2602769, 1952.
2. Capek, A., Hanc, O., and Tadra, M., Microbial Transformation of Steroids, Prague: Academia Publishing House of Czechoslovak Academy of Science, 1966.
3. Charney, W. and Herzog, H.L., Microbial Transformation of Steroids, New York: Academic Press, 1967.
4. Akhrem, A.A. and Titov, Yu.A., in Steroidy i mikroorganizmy (Steroids and Microorganisms), Moscow: Nauka, 1970.
5. Smith, L.L., in Terpenoids and Steroids., Overton, K.H., Ed., New York: Acad. Press, 1974, vol. 4, pp. 394–530.