Cita APA (7th ed.)
Washburn, B., & Washburn, B. P. The Heart of the Grand Canyon. National Geographic Society : Museum of Science.
Cita Chicago (17th ed.)
Washburn, Bradford, i Barbara P. Washburn. The Heart of the Grand Canyon. Washington, EUA : Boston, EUA: National Geographic Society : Museum of Science.
Cita MLA (9th ed.)
Washburn, Bradford, i Barbara P. Washburn. The Heart of the Grand Canyon. National Geographic Society : Museum of Science.
Atenció: Aquestes cites poden no estar 100% correctes.