Dyfyniad APA

(1970). 1971 Britannica yearbooks of science and the future. Encyclopaedia Britannica.

Dyfyniad Arddull Chicago

1971 Britannica Yearbooks of Science and the Future. Chicago: Encyclopaedia Britannica, 1970.

Dyfyniad MLA

1971 Britannica Yearbooks of Science and the Future. Encyclopaedia Britannica, 1970.

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