1. Michel, H. O., J. Lab. Clin. Med., 34, 1564 (1949).
2. Avivi, P., Simpson, S. A., Tait, J. F., and Whitehead, J. K., Proc. Radioisotope Conf., Oxford, 1954, 1, 313 (Butterworth's Scientific Publications, London, 1954).
3. Cline, J. K., U.S. Patent Office, 1934, No. 1, 957, 443.
4. Augustinsson, K.-B., in Methods of Biochemical Analysis, edit. by Glick, D., 5, 1 (Interscience Publishers, London and New York, 1957).
5. Winteringham, F. P. W., and Harrison, A., Nature, 178, 81 (1956).