APA (7th ed.) Citation

Cairns, D. S. (1938). The riddle of the world. Round table press.

Chicago Style (17th ed.) Citation

Cairns, D. S. The Riddle of the World. New York: Round table press, 1938.

MLA (9th ed.) Citation

Cairns, D. S. The Riddle of the World. Round table press, 1938.