@article{sousa_ashmawi_2015,  title={Local analgesic effect of tramadol is not mediated by opioid receptors in
               early postoperative pain in rats},  volume={65},  ISSN={0034-7094},  url={https://doi.org/10.1016/j.bjane.2014.06.006},  DOI={10.1016/j.bjane.2014.06.006},  number={3},  journal={Revista Brasileira de Anestesiologia},  publisher={Sociedade Brasileira de Anestesiologia},  author={Sousa, Angela Maria and Ashmawi, Hazem Adel},  year={2015},  month={May},  pages={186–190} }