1. Contraceptive failure in the United States;Trussell;Stud Fam Plann,1987
2. A guide to interpreting contraceptive efficacy studies;Trussell;Obstet Gynecol,1990
3. Trussell J, Grummer-Strawn L. Contraceptive failure of the ovulation method of periodic abstinence. Fam Plann Perspect 1990;22:65–75 and Int Fam Plann Perspect 1990;16:5–15.
4. Trussell J, Strickler J, Vaughan B. Contraceptive efficacy of the diaphragm, sponge and cervical cap. Fam Plann Perspect 1993;25:100–5, 135.
5. Effectiveness of the cavity-rim cervical cap;Richwald;Obstet Gynecol,1989