Ward, B. (1968). Spaceship earth. New York: Columbia University Press.
Trích dẫn kiểu ChicagoWard, Barbara. Spaceship Earth. New York: Columbia University Press, 1968.
MLA引文Ward, Barbara. Spaceship Earth. New York: Columbia University Press, 1968.
警告：這些引文格式不一定是100％准確.