1. A Manual of Implant Power Calculation;Retzlaff,1983
2. Determination of intraocular lens power: A comparison with and without ultra sound;Kraff;Ophthalmic Surg,1978
3. The human eye as an optical system;Katz,1983
4. Optics;Fincham,1980
5. Clinical results of hydrogel lens implantation;Barrett;J Cataract Refract Surg,1986