APA (7th ed.) Citation

Knowlton, P. A. (1927). Introduction to world geography. Macmillan.

Chicago Style (17th ed.) Citation

Knowlton, Philip Arnold. Introduction to World Geography. [New York, NY]: Macmillan, 1927.

MLA (9th ed.) Citation

Knowlton, Philip Arnold. Introduction to World Geography. Macmillan, 1927.

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