1. Hart, E. J., Rad. Res., 1, 53 (1957).
2. Garrison, W. M., Weeks, B. M., Ward, J. O., and Bennett, W., J. Chem. Phys., 27, 1214 (1957).
3. Northrop, J. H., Kunitz, M., and Herriott, R. M., “Crystalline Enzymes”, 28 (Columbia University Press, New York, 1948).
4. Iddles, H. A., and Jackson, C. E., Indust. Eng. Chem., Anal. Ed., 6, 454 (1934).
5. Lappin, G. R., and Clark, L. C., Anal. Chem., 23, 541 (1951).