APA (7th ed.) Citation

Parsons, P. A. (1924). An introduction to modern social problems. A. A. Knopf.

Chicago Style (17th ed.) Citation

Parsons, Philip Archibald. An Introduction to Modern Social Problems. New York: A. A. Knopf, 1924.

MLA (9th ed.) Citation

Parsons, Philip Archibald. An Introduction to Modern Social Problems. A. A. Knopf, 1924.