Keats, J. (1996). Understanding maps (2nd ed.). Longman.
Cita Chicago (17th ed.)Keats, J.S. Understanding Maps. 2nd ed. London: Longman, 1996.
Cita MLA (9th ed.)Keats, J.S. Understanding Maps. 2nd ed. Longman, 1996.
Atenció: Aquestes cites poden no estar 100% correctes.