1. Color centers, associated rare-earth ions and the origin of coloration in natural fluorites;Bill;Phys. Chem. Miner.,1978
2. Origin of coloration in some fluorites;Bill;Am. Miner.,1967
3. Theoretical survey of the sidebands of Sm+2 fluorescence in BaF2;Hurrell;Phys. Rev.,1972
4. Spectrum and symmetry of vibrations forming the vibranic wing of the 4fk-1 4fk-1 5d - 4fk luminescence of MeF2 - P3+2 crystals JAHN TELLER pseudoeffect in CeF2-Sm+2 and SrF2 - Sm2+ crystals;Ignatev;Optics Spectr.,1980
5. Fluorescence and optical maser effects in CaF2:Sm++;Kaiser;Phys. Rev.,1961