1. Vaughan and Asbury’s General Ophthalmology, 16th ed.;Riordan-Eva,2004
2. Corneal Disorders: Clinical Diagnosis and Management, 2nd ed.;Leibowitz,1998
3. Grayson’s Diseases of the Cornea, 4th ed.;Arffa,1997
4. Wolff’s Anatomy of the Eye and Orbit, 6th ed.;Last,1969
5. Stem cells and differentiation stages in the limbo-corneal epithelium.;Wolosin;Prog Retin Eye Res,2000