APA (7th ed.) Citation

Langer, W. L., & Gleason, S. E. (1968). The undeclared war, 1940-1941 / by W.L. Langer and S.E. Gleason. Peter Smith.

Chicago Style (17th ed.) Citation

Langer, W. L., and S. E. Gleason. The Undeclared War, 1940-1941 / by W.L. Langer and S.E. Gleason. Peter Smith, 1968.

MLA (9th ed.) Citation

Langer, W. L., and S. E. Gleason. The Undeclared War, 1940-1941 / by W.L. Langer and S.E. Gleason. Peter Smith, 1968.

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