APA (7th ed.) Citation

Watt, Brown, & Spencer. (1967). A history of the world in the twentieth century. Hodder and Stoughton.

Chicago Style (17th ed.) Citation

Watt, Brown, and Spencer. A History of the World in the Twentieth Century. London: Hodder and Stoughton, 1967.

MLA (8th ed.) Citation

Watt, et al. A History of the World in the Twentieth Century. Hodder and Stoughton, 1967.