National Geographic Society, Washington, D.C, WQED (Television station : Pittsburg, Pa.), Kane, D. B., Noxon, N., & Skinner, T. (1988). The explorers [videorecording]: A century of discovery. The Society.
Dyfyniad Arddull ChicagoNational Geographic Society, Washington, D.C, Pa.) WQED (Television station : Pittsburg, Dennis B. Kane, Nicolas Noxon, and Thomas Skinner. The Explorers [videorecording]: A Century of Discovery. [Washington, D.C.]: The Society, 1988.
Dyfyniad MLANational Geographic Society, Washington, D.C, et al. The Explorers [videorecording]: A Century of Discovery. The Society, 1988.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.