APA (7th ed.) Citation

Facts on File, Inc, & Sobel, L. A. (1981). Maps on file. Facts on File.

Chicago Style (17th ed.) Citation

Facts on File, Inc, and Lester A. Sobel. Maps on File. New York, N.Y.: Facts on File, 1981.

MLA (9th ed.) Citation

Facts on File, Inc, and Lester A. Sobel. Maps on File. Facts on File, 1981.