Huy, Lưu Đức, et al. “Tổng hợp 21-Acetat Pregn-4,9(11)-Dien-17α,21-Diol-3,20-Dion”. Vietnam Journal of Chemistry, vol. 52, no. 4, Sept. 2014, p. 443, doi:10.15625/0866-7144.2014-0009.