1. Transparent Recording Disc;Gregg,1969
2. Bellis, M. David Paul Gregg and the Optical Disc, from http://inventors.about.com/library/inventors/blopticaldisk.htm, Nov. 7, 2002.
3. World on a silver platter: a brief history of optical storage systems;Cellitti,2002
4. Patents and inventorship issues over the last thirty years of optical storage;Gregg,1997
5. Optical data storage;Milster,2004