APA (7th ed.) Citation

Langer, H. (1980). Thirty Years' War. Hippocrene Books.

Chicago Style (17th ed.) Citation

Langer, Herbert. Thirty Years' War. New York, N.Y.: Hippocrene Books, 1980.

MLA (9th ed.) Citation

Langer, Herbert. Thirty Years' War. Hippocrene Books, 1980.