O'Reilly, Andrea (6 de abril de 2010). Encyclopedia of Motherhood(en inglés). SAGE Publications. p. 1056. ISBN9781452266299. «The Roman Catholic church and some Protestant denominations have approved only "natural family planning" methods--including the rhythm method and periodic abstinence.»
Hatcher, RA; Trussel J; Stewart F (2000). Contraceptive Technology (18th edición). New York: Ardent Media. ISBN0-9664902-6-6. Archivado desde el original el 31 de mayo de 2008. Consultado el 1 de enero de 2008.
Dunson, D.B.; Baird, D.D.; Wilcox, A.J.; Weinberg, C.R. (1999). «Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation». Human Reproduction14 (7): 1835-1839. ISSN1460-2350. PMID10402400. doi:10.1093/humrep/14.7.1835.
Wade ME, McCarthy P, Braunstein GD, etal (October 1981). «A randomized prospective study of the use-effectiveness of two methods of natural family planning». American Journal of Obstetrics and Gynecology141 (4): 368-376. PMID7025639. doi:10.1016/0002-9378(81)90597-4.
Medina JE, Cifuentes A, Abernathy JR, etal (December 1980). «Comparative evaluation of two methods of natural family planning in Colombia». American Journal of Obstetrics and Gynecology138 (8): 1142-1147. PMID7446621. doi:10.1016/S0002-9378(16)32781-8.
Marshall J (August 1976). «Cervical-mucus and basal body-temperature method of regulating births: field trial». Lancet2 (7980): 282-283. PMID59854. doi:10.1016/S0140-6736(76)90732-7.
Frank-Herrmann P, Freundl G, Baur S, etal (December 1991). «Effectiveness and acceptability of the sympto-thermal method of natural family planning in Germany». American Journal of Obstetrics and Gynecology165 (6 Pt 2): 2052-2054. PMID1755469. doi:10.1016/s0002-9378(11)90580-8.
Frank-Herrmann P, Freundl G, Gnoth C, etal (June–September 1997). «Natural family planning with and without barrier method use in the fertile phase: efficacy in relation to sexual behavior: a German prospective long-term study». Advances in Contraception13 (2–3): 179-189. PMID9288336. doi:10.1023/A:1006551921219.
Howard, M.P.; Stanford, J.B. (1999). «Pregnancy probabilities during use of the Creighton Model Fertility Care System». Archives of Family Medicine8 (5): 391-402. PMID10500511. doi:10.1001/archfami.8.5.391.
Manders, M; McLindon, L; Schulze, B; Beckmann, MM; Kremer, JA; Farquhar, C (17 de marzo de 2015). «Timed intercourse for couples trying to conceive.». The Cochrane Database of Systematic Reviews3 (3): CD011345. PMID25775926. doi:10.1002/14651858.CD011345.pub2.
Wang X, Chen C, Wang L, Chen D, Guang W, French J (2003). «Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study». Fertil Steril79 (3): 577-84. PMID12620443. doi:10.1016/S0015-0282(02)04694-0.
Brown E (2022). «Less Like Magic, More Like a Chore: How Sex for the Purpose of Pregnancy Becomes a Third Shift for Women in Heterosexual Couples». Sociological Forum37 (2): 465-85. doi:10.1111/socf.12803.
familyplanning.net
«About us». Family of the Americas. 2006. Archivado desde el original el 13 de febrero de 2007. Consultado el 18 de marzo de 2007.
Dunson, D.B.; Baird, D.D.; Wilcox, A.J.; Weinberg, C.R. (1999). «Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation». Human Reproduction14 (7): 1835-1839. ISSN1460-2350. PMID10402400. doi:10.1093/humrep/14.7.1835.
Dunson, D.B.; Baird, D.D.; Wilcox, A.J.; Weinberg, C.R. (1999). «Day-specific probabilities of clinical pregnancy based on two studies with imperfect measures of ovulation». Human Reproduction14 (7): 1835-1839. ISSN1460-2350. PMID10402400. doi:10.1093/humrep/14.7.1835.
Wade ME, McCarthy P, Braunstein GD, etal (October 1981). «A randomized prospective study of the use-effectiveness of two methods of natural family planning». American Journal of Obstetrics and Gynecology141 (4): 368-376. PMID7025639. doi:10.1016/0002-9378(81)90597-4.
Medina JE, Cifuentes A, Abernathy JR, etal (December 1980). «Comparative evaluation of two methods of natural family planning in Colombia». American Journal of Obstetrics and Gynecology138 (8): 1142-1147. PMID7446621. doi:10.1016/S0002-9378(16)32781-8.
Marshall J (August 1976). «Cervical-mucus and basal body-temperature method of regulating births: field trial». Lancet2 (7980): 282-283. PMID59854. doi:10.1016/S0140-6736(76)90732-7.
Frank-Herrmann P, Freundl G, Baur S, etal (December 1991). «Effectiveness and acceptability of the sympto-thermal method of natural family planning in Germany». American Journal of Obstetrics and Gynecology165 (6 Pt 2): 2052-2054. PMID1755469. doi:10.1016/s0002-9378(11)90580-8.
Frank-Herrmann P, Freundl G, Gnoth C, etal (June–September 1997). «Natural family planning with and without barrier method use in the fertile phase: efficacy in relation to sexual behavior: a German prospective long-term study». Advances in Contraception13 (2–3): 179-189. PMID9288336. doi:10.1023/A:1006551921219.
Ecochard, R.; Pinguet, F.; Ecochard, I.; De Gouvello, R.; Guy, M.; Huy, F. (1998). «Analysis of natural family planning failures. In 7007 cycles of use». Contraception, Fertilité, Sexualité26 (4): 291-6. PMID9622963.
Hilgers, T.W.; Stanford, J.B. (1998). «Creighton Model NaProEducation Technology for avoiding pregnancy. Use effectiveness». Journal of Reproductive Medicine43 (6): 495-502. PMID9653695.
Howard, M.P.; Stanford, J.B. (1999). «Pregnancy probabilities during use of the Creighton Model Fertility Care System». Archives of Family Medicine8 (5): 391-402. PMID10500511. doi:10.1001/archfami.8.5.391.
Manders, M; McLindon, L; Schulze, B; Beckmann, MM; Kremer, JA; Farquhar, C (17 de marzo de 2015). «Timed intercourse for couples trying to conceive.». The Cochrane Database of Systematic Reviews3 (3): CD011345. PMID25775926. doi:10.1002/14651858.CD011345.pub2.
Hilgers T, Daly K, Prebil A, Hilgers S (October 1992). «Cumulative pregnancy rates in patients with apparently normal fertility and fertility-focused intercourse». J Reprod Med37 (10): 864-6. PMID1479570.
Wang X, Chen C, Wang L, Chen D, Guang W, French J (2003). «Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study». Fertil Steril79 (3): 577-84. PMID12620443. doi:10.1016/S0015-0282(02)04694-0.
«About us». Family of the Americas. 2006. Archivado desde el original el 13 de febrero de 2007. Consultado el 18 de marzo de 2007.
«About the Institute». Pope Paul VI Institute. 2006. Archivado desde el original el 12 de marzo de 2012. Consultado el 21 de febrero de 2012.
James B. Brown (2005). «Physiology of Ovulation». Ovarian Activity and Fertility and the Billings Ovulation Method. Ovulation Method Research and Reference Centre of Australia. Archivado desde el original el 24 de diciembre de 2005.
Hatcher, RA; Trussel J; Stewart F (2000). Contraceptive Technology (18th edición). New York: Ardent Media. ISBN0-9664902-6-6. Archivado desde el original el 31 de mayo de 2008. Consultado el 1 de enero de 2008.
James B. Brown (2005). «Physiology of Ovulation». Ovarian Activity and Fertility and the Billings Ovulation Method. Ovulation Method Research and Reference Centre of Australia. Archivado desde el original el 24 de diciembre de 2005.