Martins, Ayrton Figueredo, Anaelena Bragança de Morais, and Geisa Maria Baron. “Application of Extractive Spectrophotometric Methods for Determination of Trace Elements of Ambiental Relevance in the Thermoeletric Coal from Candiota, RS”. Ciência e Natura 6, no. 6 (December 11, 1984): 75–82. Accessed August 13, 2024. https://periodicos.ufsm.br/cienciaenatura/article/view/25071.