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2. Ward, B. A., and SERPELL, G. (1954). Ibid., 38, 397.
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4. DIXON, J. M., and PAUL, E. V. (1951). Amer. J. Ophthal., 34, 182.
5. FRIEDENWALP, J. S., OWENS, W. C., and OWENS, E. U. (1951). Trans. Amer. ophthal. Soc., 49, 207.