1. Agarwal A, Jacob S (2010) Color atlas of ophthalmology, 2nd edn. Thieme, New York, pp 133–134
2. Basak SK (2011) Jaypee gold standard mini atlas series, diseases of the cornea. JP Medical Ltd, London, p 366
3. Hoyt CS, Taylor D (2012) Pediatric ophthalmology and strabismus, 4th edn. Elsevier, Berlin, p 318
4. Hunt K (2002) Core curriculum for ophthalmic nursing, 2nd edn. Asorn, Dubuque, Iowa, pp 397–398
5. Kanski JJ, Bowling B (2011) Clinical ophthalmology: a systematic approach, 7th edn. Elsevier, London, pp 251–267