Dyfyniad APA

WORLD BOOK. (1990). WORLD BOOK'S SCIENCE DESK REFERENCE. WORLD BOOK INC.

Dyfyniad Arddull Chicago

WORLD BOOK. WORLD BOOK'S SCIENCE DESK REFERENCE. CHICAGO: WORLD BOOK INC, 1990.

Dyfyniad MLA

WORLD BOOK. WORLD BOOK'S SCIENCE DESK REFERENCE. WORLD BOOK INC, 1990.

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