Rowan JP, Simon JA, Speroff L, Ellman H (June 2006). "Effects of low-dose norethindrone acetate plus ethinyl estradiol (0.5 mg/2.5 microg) in women with postmenopausal symptoms: updated analysis of three randomized, controlled trials". Clin Ther. 28 (6): 921–32. doi:10.1016/j.clinthera.2006.06.013. PMID16860174.
Rowan JP, Simon JA, Speroff L, Ellman H (June 2006). "Effects of low-dose norethindrone acetate plus ethinyl estradiol (0.5 mg/2.5 microg) in women with postmenopausal symptoms: updated analysis of three randomized, controlled trials". Clin Ther. 28 (6): 921–32. doi:10.1016/j.clinthera.2006.06.013. PMID16860174.