1. Bieber, I.,et al. (1962).Homosexuality: A Psychoanalytic Study, Basic Books, New York.
2. Ellis, H. (1901).Studies in the Psychology of Sex, Vol. II, Davis, Philadelphia.
3. Hooker, E. (1965). An empirical study of some relations between sexual patterns and gender identity in male homosexuals. InSex Research New Developments, Holt, New York, pp. 24–52.
4. Ingham, J. (1968). Culture and personality in a Mexican village. Unpublished doctoral dissertation, University of California, Berkeley.
5. Kinsey, A.,et al. (1948).Sexual Behavior in the Human Male, Saunders, Philadelphia.