APA (7th ed.) Citation

Liberal Survey, Washington, D.C, Knapp, K., & Scull, D. H. (1939). Directory for liberals. The Liberal survey.

Chicago Style (17th ed.) Citation

Liberal Survey, Washington, D.C, Kay Knapp, and David H. Scull. Directory for Liberals. Washington, D. C.: The Liberal survey, 1939.

MLA (9th ed.) Citation

Liberal Survey, Washington, D.C, et al. Directory for Liberals. The Liberal survey, 1939.