APA (7th ed.) Citation

Raby, R. (2010). Pope Adrian IV: An Historical Sketch. Project Gutenberg.

Chicago Style (17th ed.) Citation

Raby, Richard. Pope Adrian IV: An Historical Sketch. Project Gutenberg, 2010.

MLA (9th ed.) Citation

Raby, Richard. Pope Adrian IV: An Historical Sketch. Project Gutenberg, 2010.

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