57Fe MÖSSBAUER SPECTROSCOPIC STUDIES OF STRUCTURAL CHANGES OF MONTMORILLONITE ON HEATING IN REDUCING ATMOSPHERE M. Takeda, O. Kawakami et T. Tominaga J. Phys. Colloques, 40 C2 (1979) C2-472-C2-474 DOI: 10.1051/jphyscol:19792163