^Hirst, H. "Recent progress in tungsten metallic filament lamps," The Electrical Journal, Volume LXI, May 22, 1908, pages 215-216. Retrieved December 14, 2011
^[1] Coolidge, W.D., "Metallic tungsten and some of its applications," Transactions of the American Institute of Electrical Engineers, Vol. XXXI, Part 1. June 25, 1912. Pages 1219-1228. Retrieved December 14, 2011 نسخة محفوظة 21 يناير 2020 على موقع واي باك مشين.