@article{brinkmann_santos_1971,  title={Time dependency of hydrogen - ion concentration and electric conductivity measurements in river water samples of Central Amazonia<sup>(</sup><sup>)</sup>},  volume={1},  ISSN={0044-5967},  url={https://doi.org/10.1590/1809-43921971012057},  DOI={10.1590/1809-43921971012057},  number={2},  journal={Acta Amazonica},  publisher={Instituto Nacional de Pesquisas da Amazônia},  author={Brinkmann, W.L.F. and Santos, A. dos},  year={1971},  month={Aug},  pages={57–62} }