STRUCTURAL INVESTIGATIONS OF POLYCRISTALLINE YBCO THIN FILMS AND CERAMICS BY X-RAY AND STEM F. HOSSEINI TEHRANI, J. CHAZELAS, R. KORMANN, L.M. MERCANDALLI, R. CABANEL et G. GARRY J. Phys. Colloques, 51 C1 (1990) C1-1061-C1-1066 DOI: 10.1051/jphyscol:19901165