APA (7th ed.) Citation

Knappen, M. M. (1956). An introduction to American foreign policy. Harper.

Chicago Style (17th ed.) Citation

Knappen, M. M. An Introduction to American Foreign Policy. New York: Harper, 1956.

MLA (9th ed.) Citation

Knappen, M. M. An Introduction to American Foreign Policy. Harper, 1956.

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