Encyclopedia of World Biography. "Alexander Graham Bell", Encyclopedia of World Biography. Thomson Gale. 2004. Retrieved December 20, 2009 from Encyclopedia.com.
Schoenherr, Steven. Recording Technology History: Charles Sumner Tainter and the GraphophoneArchived 2011-12-23 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.
"Volta Laboratory & Bureau". Washington D.C. National Register of Historic Places Travel Itinerary listing. National Park Service. Retrieved May 10, 2008.
tps.cr.nps.gov
"Volta Bureau". National Historic Landmark summary listing. National Park Service. Archived from the original on October 11, 2012. Retrieved May 10, 2008.
"Volta Bureau". National Historic Landmark summary listing. National Park Service. Archived from the original on October 11, 2012. Retrieved May 10, 2008.
Schoenherr, Steven. Recording Technology History: Charles Sumner Tainter and the GraphophoneArchived 2011-12-23 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.