@article{raposo_costa_barbeira_2015,  title={Simultaneous Determination of Na, K and Ca in Biodiesel by Flame Atomic
               Emission Spectrometry},  volume={26},  ISSN={0103-5053},  url={https://doi.org/10.5935/0103-5053.20140231},  DOI={10.5935/0103-5053.20140231},  number={1},  journal={Journal of the Brazilian Chemical Society},  publisher={Sociedade Brasileira de Química},  author={Raposo, Juliana D. and Costa, Letícia M. and Barbeira, Paulo Jorge S.},  year={2015},  month={Jan},  pages={147–155} }