Rietveld refinement of ´Er POT.3+´, ´Ho POT.3+´, ´Tm POT.3+´ and ´Tb POT.3+´: containing y zeolites - Doriguetto, Antonio Carlos; Mascarenhas, Yvonne Primerano; Zotin, F M Z; Trigueiro, F; Souza-Aguiar, Eduardo Falabella (Rare Earths' 2001, 2001)