1. Trip, C.A. The Homosexual Matrix. (Signet, New York, 1975).
2. Bell, A.P., Weinberg, M.S. & Hammersmith, S.K. Sexual Preference: Its Development in Men & Women. (Indiana University Press, Bloomington, 1981).
3. LeVay, S. The Sexual Brain. (MIT Press,Cambridge, MA, 1993).
4. Hamer, D.H. & Copeland, P. The Science of Desire. (Simon & Schuster, New York, 1994).
5. Hamer, D.H., Hu, S., Magnuson, V.L., Hu, N. & Pattatucci, A.M.L. A linkage between DNA markers on the X chromosome and male sexual orientation. Science 261, 321–327 (1993).