Electronic Structure of (Tl0.5Pb0.5)Sr2(Ca1-xYx)Cu2O7 (x = 0 - 0.9) at 50 K Probed by X-Ray Absorption Spectroscopy J.M. Chen, R.S. Liu et W.Y. Liang J. Phys. IV France, 7 C2 (1997) C2-523-C2-524 DOI: 10.1051/jp4/1997081