1. Proc. First Conf. on Intrauterine Contraceptive Devices: International Congress Series No. 54, Excerpta Med. Foundation, p. 69.
2. Proc. First Conf. on Intrauterine Contraceptive Devices: International Congress Series No. 54, Excerpta Med. Foundation, p. 145.
3. Additional Measures of Use-Effectiveness of Contraception
4. Social and Psychological Factors Affecting Fertility. XX. The Use, Effectiveness, and Acceptability of Methods of Fertility Control
5. Family growth in metropolitan America;Westoff,1961