"August 10, 1907; Lights! Cameras! Where action was for one brief decade, Essanay Studios, a pioneering movie studio turned Chicago into Hollywood-on-the-prairie"
April 13, 1997 · Iss. IV, pg. 2:1 · by: Michael Wilmington
Classic Images (US)
"The Father Figure of the Western Film; Broncho Billy Anderson; They All Rode in His Tracks"
June 1987 · Iss. 144, pg. 21 · by: Gunnar Lundquist
Variety (US)
"George K. Spoor"
December 2, 1953
New York Times (US)
"George K. Spoor, 81, Film Pioneer, Dies; Head of Old Essanay Concern in Chicago Devised a 3-D Picture Process in 1923"
November 25, 1953 · pg. 23:1
Moving Picture World (US)
"George K. Spoor Increases Sales and Factory Forces"