1. Davis, K. B.: Factors in the Sex Life of 2,200 Women. New York, 1929.
2. Hamilton, G. V.: A Research in Marriage. New York, 1929.
3. Rosanoff, A. J.: Manual of Psychiatry and Mental Hygiene. John Wiley, New York, 1938.
4. Ellis, Havelock: Studies in the Psychology of Sex. Sexual Inversion. F. A. Davis, Philadelphia, 1919.
5. Sadler, Wm S.: Theory and Practice of Psychiatry. C. V. Mosby, St. Louis, 1936.