1. Röntgenographische und kolloidchemische Untersuchungen über Ton
2. In this connection, see : Die Tonminerale, 2nd Edit. Verlg Chemie, Weinheim 1955;
3. and : Reference Clay Minerals. Amer. Petrol. Inst. Research Project (1949);
4. : The X-Ray Identification and Crystal Structures of Clay Minerals. Mineralogical Soc., London 1961;