^Prince, R.J.; Simmonds, M.A. (1993). "Differential antagonism by epipregnanolone of alphaxalone and pregnanolone potentiation of [3H]flunitrazepam binding suggests more than one class of binding site for steroids at GABAA receptors". Neuropharmacology. 32 (1): 59–63. doi:10.1016/0028-3908(93)90130-U. ISSN0028-3908. PMID8381526. S2CID25766028.
^Junkermann H, Runnebaum B, Lisboa BP (July 1977). "New progesterone metabolites in human myometrium". Steroids. 30 (1): 1–14. doi:10.1016/0039-128X(77)90131-3. PMID919010. S2CID28420255. In the Clauberg bioassay the 3β-hydroxy-4-pregnen-20-one shows about the same potency as progesterone (34). In regard to the biological activity of the 3α epimer no data are available.