THE STRUCTURAL Re-ARRANGEMENT IN CaF2 DUE TO TRIVALENT RARE EARTH IMPURITY IONS D. KIRO, W. LOW et E. SECEMSKIJ. Phys. Colloques, 32 C1 (1971) C1-950-C1-951DOI: https://doi.org/10.1051/jphyscol:19711341
