An ab-initio Study of Optical Properties of Perovskites : LaMO3 and YMO3 (M = Ti-Cu) M.A. Khan, S. Bouarab, A. Vega and L.C. Balbás J. Phys. IV France, 07 C1 (1997) C1-717-C1-718 DOI: 10.1051/jp4:19971292