APA (7th ed.) Citation

Heer, F. (1961). The medieval world Europa 1100 - 1350. A mentor Book.

Chicago Style (17th ed.) Citation

Heer, Friedrich. The Medieval World Europa 1100 - 1350. New York: A mentor Book, 1961.

MLA (9th ed.) Citation

Heer, Friedrich. The Medieval World Europa 1100 - 1350. A mentor Book, 1961.

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