IMPURITY CENTRES.Ni+ and Ni3+ centers in X-irradiated CaF2 J. Casas, H. W. Den Hartog et R. AlcaláJ. Phys. Colloques, 41 C6 (1980) C6-191-C6-194DOI: https://doi.org/10.1051/jphyscol:1980649
