Cu VALENCE d STATES IN HIGH-Tc SUPERCONDUCTORS FROM SOFT X-RAY FLUORESCENCE SPECTROSCOPY J.-M. MARIOT, V. BARNOLE, C.F. HAGUE, V. GEISER and H .-J . GÜNTHERODT J. Phys. Colloques, 48 C9 (1987) C9-1203-C9-1206 DOI: 10.1051/jphyscol:19879217