Smith, S. S., & Jordan, W. D. (1965). An essay on the causes of the variety of complexion and figure in the human species. Cambridge, Mass.: Belknap Press of Harvard University Press.

Smith, Samuel Stanhope, and Winthrop D. Jordan. An Essay On the Causes of the Variety of Complexion and Figure in the Human Species. Cambridge, Mass.: Belknap Press of Harvard University Press, 1965.

Smith, Samuel Stanhope, and Winthrop D. Jordan. An Essay On the Causes of the Variety of Complexion and Figure in the Human Species. Cambridge, Mass.: Belknap Press of Harvard University Press, 1965.