MÖSSBAUER SPECTRA OF STOICHIOMETRIC AND NONSTOICHIOMETRIC Fe3O4 MICROCRYSTALS H. TOPSØE, J.A. DUMESIC and M. BOUDART J. Phys. Colloques, 35 C6 (1974) C6-411-C6-413 DOI: 10.1051/jphyscol:1974680