Rankamaite from the urubu pegmatite, Itinga, Minas Gerais, Brazil: crystal chemistry and Rietveld refinement - Atencio, Daniel; Contreira Filho, Reynaldo R.; Mills, Stuart J.; Coutinho, José Moacyr Vianna; Honorato, Sara B.; Ayala, Alejandro Pedro; Ellena, Javier; Andrade, Marcelo Barbosa de (American Mineralogist, 2011)