Hîrtopanu Paulina and Andersen J. C. and Fairhurst R. J. and Ludusan N. and Jakab Gy.: Nb, Ta, Ti, ree (y) Zr, Sn, Th, U oxides from gradistea de munte rare element minerals occurrence, Sebes Mts., Romania. In: Acta mineralogica-petrographica, (7). p. 54. (2012)