Polycyclic aromatic hydrocarbons in superficial sediments of the Negro River in the Amazon region of Brazil - Souza, Hilton Marcelo de Lima; Taniguchi, Satie; Bícego, Márcia Caruso; Oliveira, Luiz Antônio de; Oliveira, Tereza Cristina Souza de; Barroso, Hiléia Santos; Zanotto, Sandra Patricia (Journal of the Brazilian Chemical Society (print), 2015)