@article{article86dcec3e,
title   = {Some observations on gold in the weathering profile at garimpo Porquinho, an Artisanal Mine in the Tapajós region, Brazilian Amazon},
author = {Oliveira, Sonia Maria Barros de and Larizzatti, João Henrique},
year = {2006},
doi = {10.5327/s1519-874x2006000100001},
journal   = {Geologia USP. Série Científica}
}