Hartley, W. H., & Vincent, W. S. (1970). American civics (3rd ed.). Harcourt brace jovanovich.
Cita Chicago (17th ed.)Hartley, William H., i William S. Vincent. American Civics. 3rd ed. New York: Harcourt brace jovanovich, 1970.
Cita MLA (9th ed.)Hartley, William H., i William S. Vincent. American Civics. 3rd ed. Harcourt brace jovanovich, 1970.
Atenció: Aquestes cites poden no estar 100% correctes.