Pinto, A.C.A. and Maia, T.F.A. 2020. Characterization of secondary deposits of columbite-tantalite minerals found in the city of Rorainópolis (RR), Brazil. International Journal for Innovation Education and Research. 8, 4 (Apr. 2020), 450–468. DOI:https://doi.org/10.31686/ijier.vol8.iss4.2299.