Schoenherr, Steven. Recording Technology History: Charles Sumner Tainter and the GraphophoneArchived December 23, 2011, at the Wayback Machine., originally published at the History Department of, University of San Diego, revised July 6, 2005. Retrieved from University of San Diego History Department website December 19, 2009. Document transferred to a personal website upon Professor Schoenherr's retirement. Retrieved again from homepage.mac.com/oldtownman website July 21, 2010.
Schoenherr, Steven. Recording Technology History: Charles Sumner Tainter and the GraphophoneArchived December 23, 2011, at the Wayback Machine., originally published at the History Department of, University of San Diego, revised July 6, 2005. Retrieved from University of San Diego History Department website December 19, 2009. Document transferred to a personal website upon Professor Schoenherr's retirement. Retrieved again from homepage.mac.com/oldtownman website July 21, 2010.