Cita APA (7a ed.)
Allen, W. L. National Geographic: Vol. 188, no. 6, December 1995. National Geographic Society.
Cita estilo Chicago (17a ed.)
Allen, William L. National Geographic: Vol. 188, No. 6, December 1995. Washington, EUA: National Geographic Society.
Cita MLA (9a ed.)
Allen, William L. National Geographic: Vol. 188, No. 6, December 1995. National Geographic Society.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.