Parker, Philip M. The 2007-2012 Outlook for Artists Chalk and Crayons, Modeling Clay and Other Modeling Material, Tempera Colors, Fingerpaint, Block Printing Ink, and Watercolors Excluding Drawing and India Ink in the United States. New York: ICON Group International, Inc., 2006.

Parker, Philip M. The 2007-2012 Outlook for Artists Chalk and Crayons, Modeling Clay and Other Modeling Material, Tempera Colors, Fingerpaint, Block Printing Ink, and Watercolors Excluding Drawing and India Ink in the United States. New York: ICON Group International, Inc., 2006.