APA (7th ed.) Citation

Sommerfield, J. (1937). Volunteer in Spain. Knopf.

Chicago Style (17th ed.) Citation

Sommerfield, John. Volunteer in Spain. New York [N.Y.]: Knopf, 1937.

MLA (9th ed.) Citation

Sommerfield, John. Volunteer in Spain. Knopf, 1937.

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