@article{szpigel_durães_steffens_2007,  title={Contribution from Drell-Yan processes to the emission spectrum in solar flares},  volume={37},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97332007000100017},  DOI={10.1590/S0103-97332007000100017},  number={1a},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Szpigel, S. and Durães, F. O. and Steffens, F. M.},  year={2007},  month={Mar},  pages={52–55} }