THE Ba-PROBLEM IN CVD-YBa2 Cu3 O7-[MATH] HTC SUPERCONDUCTORS E. FITZER, H. OETZMANN, F. SCHMADERER et G. WAHL J. Phys. IV France, 02 C2 (1991) C2-713-C2-720 DOI: 10.1051/jp4:1991286