Borgerson, Bruce (1 November 2003), "Is it P.A. or SR?", Sound & Video Contractor, Prism Business Media, archived from the original on 1 December 2008, retrieved 18 February 2007
Borgerson, Bruce (1 November 2003), "Is it P.A. or SR?", Sound & Video Contractor, Prism Business Media, archived from the original on 1 December 2008, retrieved 18 February 2007