Guttmacher Institute. Choice of Contraceptives. The Medical Letter on Drugs and Therapeutics. 1992, 34 (885): 111–114. PMID 1448019. Hatcher, RA; Trussel J, Stewart F, et al. Contraceptive Technology Sixteenth Revised. New York: Irvington Publishers. 1994. ISBN 0-8290-3171-5.引文使用过时参数coauthors (帮助)
Guttmacher Institute. Choice of Contraceptives. The Medical Letter on Drugs and Therapeutics. 1992, 34 (885): 111–114. PMID 1448019. Hatcher, RA; Trussel J, Stewart F, et al. Contraceptive Technology Sixteenth Revised. New York: Irvington Publishers. 1994. ISBN 0-8290-3171-5.引文使用过时参数coauthors (帮助)