Englund , D. E., and E. D. B. Johansson. “Oral Versus Vaginal Absorption in Oestradiol in Postmenopausal Women. Effects of Different Particles Sizes”. Upsala Journal of Medical Sciences, vol. 86, no. 3, Sept. 1981, pp. 297-0, doi:10.3109/03009738109179241.