Tm3+ and Yb3+ in TmXO4 and Yb3+ in YbXO4 (X = P, V) from 169Tm and 170 Yb Mössbauer measurements J.A. Hodges J. Phys. France, 44 7 (1983) 833-839 DOI: 10.1051/jphys:01983004407083300
