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2. HALLDfN, U. (1952). Acta ophthal. (Kbh.), Suppl.
3. LYLE, T. KEITH, and FOLEY, J. (1955). Brit. J. Ophthal., 39, 474.
4. MARAINI, G., and PASINO, L. (1964). Ibid., 48, 439.
5. MARAINI, G., and PASINO, L. (1965). Ibid., 49, 154.