1. ar-Râzî on the hidden illness;Rosenthal;Bull. Hist. Med.,1978
2. A genetic study of male sexual orientation;Bailey;Arch. Gen. Psychiatry,1991
3. Constitution and Disease;Bauer,1942
4. Heat Kinsey Rapport over vrowelijke en mannelijke homoseksualiteit;Bell,1979
5. Sexual Preference;Bell,1981