METAL-NON METAL TRANSITION OF Ni1-xS AND NiS SUBSTITUTED by Se, As and Fe : TRANSPORT PROPERTIES AND STRUCTURAL ASPECT E. BARTHELEMY, C. CHAVANT, G. COLLIN and O. GOROCHOV J. Phys. Colloques, 37 C4 (1976) C4-17-C4-22 DOI: 10.1051/jphyscol:1976403