Cita APA (7a ed.)
Garret, W. E. National Geographic: Vol. 171, no. 6, June 1987. National Geographic Society.
Cita estilo Chicago (17a ed.)
Garret, Wilbur E. National Geographic: Vol. 171, No. 6, June 1987. Washington, EUA: National Geographic Society.
Cita MLA (9a ed.)
Garret, Wilbur E. National Geographic: Vol. 171, No. 6, June 1987. National Geographic Society.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.