Cita APA (7th ed.)

Letham, L. (1998). GPS made easy: Using global positioning systems in the outdoors (2nd ed.). Mountaineers.

Cita Chicago (17th ed.)

Letham, Lawrence. GPS Made Easy: Using Global Positioning Systems in the Outdoors. 2nd ed. Seattle: Mountaineers, 1998.

Cita MLA (9th ed.)

Letham, Lawrence. GPS Made Easy: Using Global Positioning Systems in the Outdoors. 2nd ed. Mountaineers, 1998.