Littleton, Lynna A.· Engebretson, Joan C. (14 Οκτωβρίου 2004). Maternity Nursing Care. Cengage Learning. σελ. 195. ISBN9781401811921. Ανακτήθηκε στις 9 Νοεμβρίου 2013.
«Ultrasound instead of last menstrual period as the basis of gestational age assignment». Ultrasound in Obstetrics & Gynecology1 (3): 212–9. May 1991. doi:10.1046/j.1469-0705.1991.01030212.x. PMID12797075.
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Baird, D. T.; Balen, A.; Escobar-Morreale, H. F.; Evers, J. L. H.; Fauser, B. C. J. M.; Franks, S.; Glasier, A.; Homburg, R. και άλλοι. (2012). «Health and fertility in World Health Organization group 2 anovulatory women». Human Reproduction Update18 (5): 586–99. doi:10.1093/humupd/dms019. PMID22611175.
«Ovulation inhibition doses of progestins: a systematic review of the available literature and of marketed preparations worldwide». Contraception84 (6): 549–57. December 2011. doi:10.1016/j.contraception.2011.04.009. PMID22078182.
«Ultrasound instead of last menstrual period as the basis of gestational age assignment». Ultrasound in Obstetrics & Gynecology1 (3): 212–9. May 1991. doi:10.1046/j.1469-0705.1991.01030212.x. PMID12797075.
«Time of implantation of the conceptus and loss of pregnancy». The New England Journal of Medicine340 (23): 1796–9. June 1999. doi:10.1056/NEJM199906103402304. PMID10362823.
Baird, D. T.; Balen, A.; Escobar-Morreale, H. F.; Evers, J. L. H.; Fauser, B. C. J. M.; Franks, S.; Glasier, A.; Homburg, R. και άλλοι. (2012). «Health and fertility in World Health Organization group 2 anovulatory women». Human Reproduction Update18 (5): 586–99. doi:10.1093/humupd/dms019. PMID22611175.
«Ovulation inhibition doses of progestins: a systematic review of the available literature and of marketed preparations worldwide». Contraception84 (6): 549–57. December 2011. doi:10.1016/j.contraception.2011.04.009. PMID22078182.