Nordan, Lee T. “Keratoconus: Diagnosis and Treatment”. International Ophthalmology Clinics, vol. 37, no. 1, 1997, pp. 51-63, https://doi.org/10.1097/00004397-199703710-00005.
Nordan, L. T. (1997). Keratoconus: Diagnosis and Treatment. International Ophthalmology Clinics, 37(1), 51-63. https://doi.org/10.1097/00004397-199703710-00005
Nordan LT. Keratoconus: Diagnosis and Treatment. International Ophthalmology Clinics. 1997;37(1):51-63.