APA (7th ed.) Citation

Simpson, G. G. (1980). Why and how: Some problems and methods in historical biology. Pergamon Press.

Chicago Style (17th ed.) Citation

Simpson, George Gaylord. Why and How: Some Problems and Methods in Historical Biology. Oxford ; New York: Pergamon Press, 1980.

MLA (9th ed.) Citation

Simpson, George Gaylord. Why and How: Some Problems and Methods in Historical Biology. Pergamon Press, 1980.