Levenson, Harvey R. (2006), Current Trends in Virtual Proofing(PDF), Graphic Communications Institute at Cal Poly, p. 4–5, archived from the original(PDF) on 2011-07-04, retrieved 2015-05-27
Levenson, Harvey R. (2006), Current Trends in Virtual Proofing(PDF), Graphic Communications Institute at Cal Poly, p. 4–5, archived from the original(PDF) on 2011-07-04, retrieved 2015-05-27