1. R. W. Wheat, “Methods in Enzymology,” Vol. VIII, ed. by E. F. Neufeld and V. Ginsburg, Academic Press Inc., New York. N.Y., 1966, p. 69.
2. N. L. Allport, “Colorimetric Analysis,” Vol. I, Chapman and Hall Ltd., 1957, p. 82.
3. H. Tuppy and A. Gottschalk, “Glycoprotein,” BBA Library, Vol. 5, ed. by A. Gottschalk, Elsevier Publishing Co., Amsterdam, 1972, p. 404.