1. Barr JT 2004 Annual Report. Contact Lens Spectrum 2005
2. Leonardo and contact lenses;Hofstetter;Am J Optom Arch Am Acad Optom,1953
3. Descartes��� contact lens;Enoch;Am J Optom Arch Am Acad Optom,1956
4. History and Development of Contact Lenses;Barr,2005
5. Historical Development;Mandell,1988