APA (7th ed.) Citation

Sue, E., & Donovan, A. L. (2006). A Cardinal Sin. Project Gutenberg.

Chicago Style (17th ed.) Citation

Sue, Eugène, and Alexina Loranger Donovan. A Cardinal Sin. Project Gutenberg, 2006.

MLA (9th ed.) Citation

Sue, Eugène, and Alexina Loranger Donovan. A Cardinal Sin. Project Gutenberg, 2006.

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