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3. 3) H. Tanaka: Kogyokagaku Zasshi, 62 (1959), 58.
4. 4) B. Yoshiki: Kobustukogaku, (1958), Gihodo, Tokyo, Japan.
5. 5) R. C. Mackenzie: The Differential Thermal Investigation of Clay, (1957), Mineralogical Society, London.