[1] Blanc A, McEvoy M, Plank R. Architecture and construction in steel [M]. E & FN SPON, 1993. 589.
[2] Miller T. Sketchup review [EB/OL]. http://www.digitalcad.com/2001/02-feb/reviews/sketchup/sketchup.htm. 2001-02-12/2003-02.
[3] Greenberger D. Lighting the way [EB/OL]. http://www.cadenceweb.com/features/interviews/greenberg.html. 2001-03-18/2003-03.