1. Professional Database Analysis System (PRODAS) Reference Manual, Version 3.0,1985
2. Astigmatic difference in refractive error;Naylor;Br J Ophthalmol,1968
3. Calculation of the change in corneal astigmatism following cataract extraction;Cravy;Ophthalmic Surg,1979
4. The pathophysiology of corneal astigmatism after cataract extraction;Jaffe;Trans Am Acad Ophthalmol Otolaryngol,1975
5. Small incisions to control astigmatism during cataract surgery;Neumann;J Cataract Refract Surg,1989