1. Burt, J. J. and Brower, Linda A.; Education for Sexuality; Concepts and Programs for Teaching; W. B. Sandero Company, Philadelphia, 1970.
2. Israel, S. L. Diagnosis and Treatment of Menstrual Disorders and Sterility, 5th edition, N.Y. Hoeber Medical Division, Harper and Row Publishers, 1967.
3. Zacharias, Leona; Wurtman, R. J.; and Schatzoff, M; Sexual Maturation in Contemporary American Girls, American Journal of Obstetrics and Gynecology 108: 833-846, November 1, 1970.