APA (7th ed.) Citation

Watt, D. C., Spencer, F., & Brown, N. (1968). A history of the world in the twentieth century. W. Morrow.

Chicago Style (17th ed.) Citation

Watt, Donald Cameron, Frank Spencer, and Neville Brown. A History of the World in the Twentieth Century. New York: W. Morrow, 1968.

MLA (8th ed.) Citation

Watt, Donald Cameron, et al. A History of the World in the Twentieth Century. W. Morrow, 1968.