1. Brash, J. C.: The Etiology of Irregularities and Malocclusion of the Teeth, page 246.
2. Wallace, J. Sim: J. A. D. A. 19: 1116.
3. Jennings, H. S.: Biologic Basis of Human Nature, New York, W. W. Norton & Co., Inc.
4. Stockard, C. R.: Physical Basis of Personality, New York, W. W. Norton & Co., Inc.
5. The Genetics of Modified Endocrine Secretion and Associated Form Patterns Among Dog Breeds;Stockard,1932