INFLUENCE OF X-RAYS, LIGHT AND ANNEALING ON THE Fe-CHARGE-STATES IN LiNbO3 : Fe H.D. Pfannes, J. Lauer, W. Keune, Y. Maeda et H. Sakai J. Phys. Colloques, 41 C1 (1980) C1-453-C1-454 DOI: 10.1051/jphyscol:19801177