A.M. Pak, Yu.A. Rozhnova, S.V. Kuznetsov, A.V. Ryabova, D.V. Pominova, V.V. Voronov, P.P.  Fedorov. Efficient visible range SrF₂:Yb:Er- and SrF₂:Yb:Tm-based upconversion luminophores // J. Fluor. Chem. 194 (2017) 6–22. https://doi.org/10.1016/j.jfluchem.2016.12.002