References
- Frank-Herrmann P, Freundl G, Gnoth C, et al. 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. Adv Contracept 1997;13:179–89
- The European Natural Family Planning Study Groups. Prospective European multi-center study of natural family planning (1989-1992): interim results. Adv Contracept 1993;9:269–83
- The European Natural Family Planning Study Groups. European multicenter study of natural family planning (1989-1995): efficacy and drop-out. Adv Contracept 1996;15:69–83
- Gnoth C, Frank-Herrmann P, Bremme M, et al. How do self-observed symptoms correlate with ovulation? Zentralbl Gynakol 1996;118:650–4
- Gnoth C, Bremme M, Klemm R, et al. Research and quality control in natural family planning with relational database systems. Adv Contracept 2000;15: 375–80
- Dickey RP. Managing Contraceptive Pill Patients. Dallas: EMIS, 2000
- Dennerstein L, Gotts G, Brown JB. Effects of age and non-hormonal contraception on menstrual cycle characteristics. Gynecol Endocrinol 1997;11: 127–33
- Lenton EA, Weston GA, Cook ID. Problems in using basal body temperature recordings in an infertility clinic. Br Med J1977;1:803–5
- Dunson DB, Weinberg CR, Baird DD, et al. Assesing human fertility using several markers of ovulation. Stat Med 2001;20:965–78
- Rice-Wray E, Corren S, GorodooskyJ. Return of ovulation after discontinuance of oral contracep-tives. Fertil Steril 1967;18:212–18
- Buttram VC, Vanderheyden JD, Besch PK, et al. Post 'pill' amenorrhoea. Int J Fertil 1974;19:37–44
- Van Campenhout J, Blanchet P, Beauregard H, et al. Amenorrhoea following the use of oral contraceptives. Fertil Steril 1977;28:728–32
- Vessey MP, Wright NH, McPhearson K, et al. Fertility after stopping different methods of contraception. Br Med J 1978;1:265–7
- Bracken MB, Hellenbrand KG, Holford TR. Conception delay after oral contraceptive use: the effect of the estrogen dose. Fertil Steril 1990;53: 21–7
- Chasan-Taber L, Willet WC, Stampfer MJ, et al. Oral contraceptives and ovulatory causes ofdelayed fertility. 1997;146:258–65
- Larsson-Cohn U. The length of the first three menstrual cycles after combined oral contraceptive treatment. Acta Obstet Gynecol Scand 1969;48: 416–22
- Pellicier A, Gaitan P, Neuspiller F, et al. Ovarian follicular dynamics: from basic science to clinical practice. J Reprod Immunol 1998;39:29–61
- Baird DD, McConnaughey DR, Weinberg CR, et al. Application of a method for estimating day of ovulation using urinary estrogen and progester-one metabolites. Epidemiology 1995;5:547–50
- Gnoth C. Approaches to natural family planning. Fertil Steril 2000;6:1262