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3. BEVERLEY, J. K. A., BEATTIE, C. P., and ROSEMAN, C. (1954). J. Hyg., 52, 37.
4. BJORK, A. (1947). Acta ophthal. (Kbh.), 25, 127.
5. BLEGVAD, 0. (1941). Ibid., 19, 219.