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3. 3) T.F. O’Brien, T. V. Bommaraju, F. Hine: Handbook of Chlor-Alkali Technology, Vol. I: Fandamentals, (Springer, New York, 2005), pp. 24-26.
4. 4) Soda Gijutsu Hand Book 2009: (Japan Soda Industry Association, 2009), p. 66.
5. 5) T. Shimamune, Y. Nakajima, S. Nakamatsu: Hyomengijutsu, 42 (1991), 783-787.