Richard J Fehring, D Lawrence and C Sauvage. "A Comparison of Self-esteem, Spiritual Well-being, and Intimacy in Couples Using Natural Family Planning with Couples Using Oral Contraceptives" International Review of Natural Family Planning Vol. 13 Iss. 3 and 4 (1989)
Available at: http://works.bepress.com/richard_fehring/39/