APA (7th ed.) Citation

Martel, C., Churchill, G. M., & Perley, C. W. (1920). Classification. Class H: Social sciences (2nd edition.). U. S. Government Printing Office.

Chicago Style (17th ed.) Citation

Martel, Charles, G. M. Churchill, and Clarence W. Perley. Classification. Class H: Social Sciences. 2nd edition. Washington: U. S. Government Printing Office, 1920.

MLA (9th ed.) Citation

Martel, Charles, et al. Classification. Class H: Social Sciences. 2nd edition. U. S. Government Printing Office, 1920.