ORIENTATION RELATIONSHIPS, MICROSTRUCTURE AND ELECTRICAL BEHAVIOUR OF GRAIN BOUNDARIES IN CERAMIC SUPERCONDUCTORS J. Y. LAVAL, C. DELAMARRE, M. H. BERGER et C. CABANELJ. Phys. Colloques, 51 C1 (1990) C1-991-C1-996DOI: https://doi.org/10.1051/jphyscol:19901154