APA (7th ed.) Citation

Waddell, C. W. (1918). An introduction to child psychology. Houghton-Mifflin Company.

Chicago Style (17th ed.) Citation

Waddell, Charles W. An Introduction to Child Psychology. Boston, New York [etc.]: Houghton-Mifflin Company, 1918.

MLA (8th ed.) Citation

Waddell, Charles W. An Introduction to Child Psychology. Houghton-Mifflin Company, 1918.