1. Gebhard, PH. Incidence of overt homosexuality in the United States and Western Europe. In: Livingood JM, ed. National Institute of Mental Health Task Force on Homosexuality: Final Report and Background Papers. Rockville, MD: National Institute of Mental Health; 1972. See also: http://www.kinseyinstitute.org/resources/bib-homoprev.html
2. Prevalence and patterns of same-gender sexual contact among men;Fay;Science,1989
3. Homophobia among doctors;Rose;BMJ,1994
4. Homosexuality, Bisexuality and Sexual Orientation;Bradford,2012
5. Seeking and engaging in Internet sex: A survey of patients attending genitourinary medicine clinics in Plymouth and in London;Malu;Int J STD AIDS,2004