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- [151a.] United States of America Standards Institute, Z44-1942.
- [152.] Van den Akker, J. A., J. Opt. Soc. Am. '27, 401 (1937).
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- [163.] Zerban, F. W., J. IMartin, and C. Erb, ibid. 24, 168
(After Helmholtz.) Note that the macular pigment acts as a yellow filter interposed between vitreous humor C and retina t.
☆ U.S. GOVERNMENT PRINTING OFFICE: 1967 O 272-747
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