APA (7th ed.) Citation

Horne, C. F., Austin, W. F., Rudd, J., & Johnson, R. (2003). The Great Events by Famous Historians, Volume 05 (From Charlemagne to Frederick Barbarossa). Project Gutenberg.

Chicago Style (17th ed.) Citation

Horne, Charles F., Walter F. Austin, John Rudd, and Rossiter Johnson. The Great Events by Famous Historians, Volume 05 (From Charlemagne to Frederick Barbarossa). Project Gutenberg, 2003.

MLA (9th ed.) Citation

Horne, Charles F., et al. The Great Events by Famous Historians, Volume 05 (From Charlemagne to Frederick Barbarossa). Project Gutenberg, 2003.

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