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2. H. Haglund, “Methods of Biochemical Analysis,” Vol. XIX (Isoelectric Focusing in pH Gradients– A Technique for Fractionation and Characterization of Ampholytes), LKB-Produkter AB, Stockholm, Sweden.
3. E. J. Cohn and J. T. Edsall, “Proteins, Amino Acids and Peptides,” Reinhold Publishing Corporation, New York, N. Y., 1950, pp. 370–381.