@article{costa_ferreira_nogueira_nóbrega_2005,  title={Use of factorial design for optimization of microwave-assisted digestion of lubricating oil},  volume={16},  ISSN={0103-5053},  url={https://doi.org/10.1590/S0103-50532005000700027},  DOI={10.1590/S0103-50532005000700027},  number={6a},  journal={Journal of the Brazilian Chemical Society},  publisher={Sociedade Brasileira de Química},  author={Costa, Letícia M. and Ferreira, Sérgio L. C. and Nogueira, Ana Rita A. and Nóbrega, Joaquim A.},  year={2005},  month={Nov},  pages={1269–1274} }