APA (7th ed.) Citation

Palmer, A. (1979). The Facts on File dictionary of 20th century history. Facts on File.

Chicago Style (17th ed.) Citation

Palmer, Alan. The Facts on File Dictionary of 20th Century History. New York: Facts on File, 1979.

MLA (9th ed.) Citation

Palmer, Alan. The Facts on File Dictionary of 20th Century History. Facts on File, 1979.