APA (7th ed.) Citation

Gilbert, M. C., & Gilbert, R. W. (1951). Origin and development of the human race. Christopher.

Chicago Style (17th ed.) Citation

Gilbert, Mabel Crawley, and Ross Winthrop Gilbert. Origin and Development of the Human Race. Boston: Christopher, 1951.

MLA (9th ed.) Citation

Gilbert, Mabel Crawley, and Ross Winthrop Gilbert. Origin and Development of the Human Race. Christopher, 1951.