Cita APA (7th ed.)
National Geographic Society (U.S.). (1991). National Geographic picture atlas of our world. The National Geographic Society.
Cita Chicago (17th ed.)
National Geographic Society (U.S.). National Geographic Picture Atlas of Our World. Washington D.C: The National Geographic Society, 1991.
Cita MLA (9th ed.)
National Geographic Society (U.S.). National Geographic Picture Atlas of Our World. The National Geographic Society, 1991.
Atenció: Aquestes cites poden no estar 100% correctes.