1. M. Tolkowsky ,Diamond Design: A Study of the Reflection and Refraction of Light in a Diamond, Spon & Chamberlain, New York (1919), 〈http://www.folds.net/diamond_design/index.html〉.
2. a description of the FireScope® is given by R. Von Sternberg , “Today’s Revolution in Diamond Cutting,” (2002), 〈http://www.eightstar.com/images/Eightstar_Diamond.pdf〉.
3. see also, A. GilbertsonLetting Light Speak for Iitself: An Introduction to Diamond Cut Grading, Diamond Profile, Inc., Portland, Oreg. (1998).