APA (7th ed.) Citation

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

Chicago Style (17th ed.) Citation

Olson, Robert Goodwin, and Robert G. Olson. An Introduction to Existentialism. Dover Pubs, 1962.

MLA (9th ed.) Citation

Olson, Robert Goodwin, and Robert G. Olson. An Introduction to Existentialism. Dover Pubs, 1962.

Warning: These citations may not always be 100% accurate.