1. Allegheny Technologies, “Grade Specifications and Application Chart,” retrieved 12 November 2007 from www.tungstenprod.com/downloads/ATI_Firth_Sterling_Grade_Chart.pdf.
2. Chang-Soo Kim, Ted R. Massa, and Gregory S. Rohrer, “Modeling the Relationship between Microstructural Features and the Strength of WC-Co Composite” (2004), http://mimp.materials.cmu.edu/papers/2006-01.pdf .
3. Petr Velecky and Jaroslav Pospisil, “Digital Image Evaluation of Metallographic Microstructure of Sintered Carbides” (1999), p. 8; http://publib.upol.cz/:_obd/fulltext/physic38/physic38-10.pdf .
4. J. Gurland, “Application of Quantitative Microscopy to Cemented Carbides” (electronic version), ASTM International (January 1984).
5. International Tungsten Industry Association, “Cemented Carbides,” retrieved 12 November 2007 from www.itia.info/Default.asp?Page=53.