Dyfyniad APA

(1971). Evolution by natural selection. New York: Johnson Reprint Corporation.

Dyfyniad Arddull Chicago

Evolution By Natural Selection. New York: Johnson Reprint Corporation, 1971.

Dyfyniad MLA

Evolution By Natural Selection. New York: Johnson Reprint Corporation, 1971.

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