Oliveira, S. M. B. de, & Larizzatti, J. H. (2006). Some observations on gold in the weathering profile at Garimpo Porquinho, an artisanal mine in the Tapajós Region, Brazilian Amazon . Geologia USP. Série Científica, 5(2), 1-11. https://doi.org/10.5327/S1519-874X2006000100001