APA (7th ed.) Citation

Whitehead, A. N. (1968). Modes of thought (9. print.). Free Press.

Chicago Style (17th ed.) Citation

Whitehead, Alfred North. Modes of Thought. 9. print. New York: Free Press, 1968.

MLA (9th ed.) Citation

Whitehead, Alfred North. Modes of Thought. 9. print. Free Press, 1968.