APA (7th ed.) Citation

Willoughby, W. F. (1919). An introduction to the study of the government of modern states. The Century co.

Chicago Style (17th ed.) Citation

Willoughby, William Franklin. An Introduction to the Study of the Government of Modern States. New York: The Century co, 1919.

MLA (9th ed.) Citation

Willoughby, William Franklin. An Introduction to the Study of the Government of Modern States. The Century co, 1919.