1. Dienst, S. G. (1961). J. Lab. clin. Med., 58, 149.
2. Fenton, J. C. B. (1960). Proc. Ass. clin. Biochemists, 1, 36.
3. Fenton, J. C. B. (1962). Clin. chim. Acta, 7, 163.
4. Horn, D. B., and Squire, C. R. (1966). Ibid., 14, 185.
5. Perea, V. D., and Nelson, R. S. (1964). Ibid., 9, 13.