Thomas Commerford Martin, The Inventions, Researches and Writings of Nikola Tesla: With Special Reference to His Work in Polyphase Currents and High Potential Lighting, Electrical Engineer - 1894, Chapter XLII, page 485 [۲]
Šarboh, Snežana (18–20 October 2006). "Nikola Tesla's Patents"(PDF). Sixth International Symposium Nikola Tesla. Belgrade, Serbia. p. 6. Archived from the original(PDF) on 30 October 2007. Retrieved 8 October 2010.
Hugo Gernsback, "Tesla's Egg of Columbus, How Tesla Performed the Feat of Columbus Without Cracking the Egg" Electrical Experimenter, 19 March 1919, p. 774 [۱]
Šarboh, Snežana (18–20 October 2006). "Nikola Tesla's Patents"(PDF). Sixth International Symposium Nikola Tesla. Belgrade, Serbia. p. 6. Archived from the original(PDF) on 30 October 2007. Retrieved 8 October 2010.