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3. New photokeratoscope utilizing a hemispherical object surface;Fincham;Medical and Biological Illustration,1953
4. New photokeratoscope utilizing a hemispherical object surface;Knoll;J. Opt. Soc. Am.,1957
5. Photographic analysis of the ocular dioptric components;Ludlum;Am. J. Optom. Physiol. Opt.,1967