M P Rubinstein, S Sud, The use of hybrid lenses in management of the irregular cornea, Contact Lens & Anterior Eye, 3 22, 1999, עמ' 87-90 doi: 10.1016/s1367-0484(99)80044-7
M. A. Javadi, B. F. Motlagh, M. R. Jafarinasab, Z. Rabbanikhah, A. Anissian, H. Souri, S. Yazdani, Outcomes of penetrating keratoplasty in keratoconus, Cornea, 8 24, 2004, עמ' 941-946 doi: 10.1097/01.ico.0000159730.45177.cd