Ward, B. (1972). Only the earth: The care and maintenance of a small planet. New York: Pengiun Books.
Trích dẫn kiểu ChicagoWard, Barbara. Only the Earth: The Care and Maintenance of a Small Planet. New York: Pengiun Books, 1972.
MLA引文Ward, Barbara. Only the Earth: The Care and Maintenance of a Small Planet. New York: Pengiun Books, 1972.
警告：這些引文格式不一定是100％准確.