Synthesis, characterization and spectroscopic investigation of new tetrakis (acetylacetonato)thulate(III) complexes containing alkaline metals as countercations - Guedes, M. A.; Paolini, Tiago Becerra; Felinto, Maria Claudia França da Cunha; Kai, J.; Malta, Oscar L; Nunes, Luiz Antônio de Oliveira; Brito, Hermi Felinto de (Journal of Luminescence, 2011)