Dyfyniad APA

(1972). guide to the natural world and index to the Life nature Library. Time-Life Books.

Dyfyniad Arddull Chicago

Guide to the Natural World and Index to the Life Nature Library. New York: Time-Life Books, 1972.

Dyfyniad MLA

Guide to the Natural World and Index to the Life Nature Library. Time-Life Books, 1972.

Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.