APA (7th ed.) Citation

Olson, R. G. (1962). An introduction to existentialism. Dover Publications.

Chicago Style (17th ed.) Citation

Olson, Robert Goodwin. An Introduction to Existentialism. New York: Dover Publications, 1962.

MLA (9th ed.) Citation

Olson, Robert Goodwin. An Introduction to Existentialism. Dover Publications, 1962.