1. Knoop, F., Hofmeister's Beitr., 6, 150 (1904).
2. Breusch, F. L., “Advances in Enzymology”, 8, 343 (1948).
3. Synerholm, M. E., and Zimmerman, P. W., Contrib. Boyce Thomp. Inst., 14, 369 (1947).
4. Porteous, J. W., and Williams, R. T., Biochem. J., 44, 46 (1949).
5. Fawcett, C. H., Thesis, London (1951).