APA (7th ed.) Citation

Northrop, E. P. (1944). Riddles in mathematics: A book of paradoxes. D. Van Nostrand Company, Inc.

Chicago Style (17th ed.) Citation

Northrop, Eugene P. Riddles in Mathematics: A Book of Paradoxes. New York: D. Van Nostrand Company, Inc, 1944.

MLA (9th ed.) Citation

Northrop, Eugene P. Riddles in Mathematics: A Book of Paradoxes. D. Van Nostrand Company, Inc, 1944.