RELAXATION SUPERMATRICES AND RELAXATION MODELS IN THE INTERPRETATION OF MOSSBAUER PARAMAGNETIC RELAXATION SPECTRA C. CHOPIN, D. SPANJAARD et F. HARTMANN-BOUTRON J. Phys. Colloques, 37 C6 (1976) C6-73-C6-78 DOI: 10.1051/jphyscol:1976618