APA (7th ed.) Citation

Langer, W. L., & Gleason, S. E. (1968). The undeclared war, 1940-1941. P. Smith.

Chicago Style (17th ed.) Citation

Langer, William L., and S. Everett Gleason. The Undeclared War, 1940-1941. Gloucester, Mass: P. Smith, 1968.

MLA (9th ed.) Citation

Langer, William L., and S. Everett Gleason. The Undeclared War, 1940-1941. P. Smith, 1968.