MÖSSBAUER STUDY OF THERMAL DECOMPOSITION PROCESSES OF PYCITE-BEARING POLYMETALLIC DRES D.N. Abishev, Yu.B. Voitkovskii, N.N. Razumovskaya, L.J. Sergasina, A.K. Kobzhasov and D.K. Abdrakhmanova J. Phys. Colloques, 41 C1 (1980) C1-397-C1-398 DOI: 10.1051/jphyscol:19801153