APA (7th ed.) Citation

American Map Company (New York, N.Y.). (1970). County outline Maryland. American Map Company, Inc..

Chicago Style (17th ed.) Citation

American Map Company (New York, N.Y.). County Outline Maryland. [New York]: American Map Company, Inc., 1970.

MLA (9th ed.) Citation

American Map Company (New York, N.Y.). County Outline Maryland. American Map Company, Inc., 1970.