1. H. Neurath, “The Enzyme,” Vol. IV, Academic Press Inc., New York, N.Y. 1960, p. 37.
2. P. H. Petra, “Method in Enzyrnology,” Vol. XIX, Academic Press Inc., New York, N.Y. 1970, p. 460.
3. J. Sodek and T. Hofmann, “Method in Enzymology,” Vol. XIX, Academic Press Inc., New York, N.Y. 1970, p. 386.