M. Elisa, B. A.  Sava, I. C.  Vasiliu, R. C. Monteiro, J. P. Veiga, L.  Ghervase, I. D. Feraru, C. R. Iordanescu, Optical and structural characterization of samarium and europium-doped phosphate glasses, J NON-CRYST SOLIDS, no. 369, pp. 55-60, 0022-3093, 2013