- Aerial survey, Manhattan Island, New York City. Map. New York: The Corporation, 1921. Lib. of Cong. Web. 20 April. 2014.
- Heighton, Steven. “Story of a Jazz Age Murder.” The New York Times. The New York Times Company, 17 June 2011. Web. 2 April 2014.
- Lax-Salinas, Joey. “New York City Soho Shopping District on Broadway.” Photograph. Flickr. 23 May 2011. Web. 20 April 2014.
- Lin, Shenghung. “Allan Poe would love the wall.” Photograph. Flickr. 16 April 2010. Web. 20 April 2014.
- Poe, Edgar Allan. The Cask of Amontillado. 1846. Web. 20 April 2014.
- The Sophie Treadwell Collection. University of Arizona Department of Theatre Arts and the Univeristy of Arizona Library Special Collections, 2001. Web. 20 April 2014.
- Treadwell, Sophie. Machinal. The Norton Anthology of Drama. Ed. Gainor, J. Ellen, Garner Jr., Stanton B., and Puchner, Martin. New York: Norton, 2014. 573-633. Print.