Thomson, J.A., and Geddes, P. Problem of Sex. New York, 1912.
Westermarck, Edward. History of Human Marriage. New York, 1903.
Wilson, R.N. American Boy and the Social Evil. Philadelphia, 1905.
Zenner, Philip. Education in Sexual Physiology and Hygiene. Cincinnati, 1910.
CHAPTER III
Physiological Aspects
Reproduction
Exner, M.J. The Physician's Answer. New York, 1913.
Howell, W.H. Textbook of Physiology. Ed. 4. Philadelphia, 1911.
Landois, Leonard. Textbook of Human Physiology. Ed. 10. Philadelphia, 1904.