OSORIO-GUTIÉRREZ, C. I.; ORTIZ-GÓMEZ, G. A.; VALENCIA-RÍOS, J. F.; ARANGO-GÓMEZ, F. Comparison among subarachnoid opioid mix for cesarean section – An observational study. Colombian Journal of Anesthesiology, v. 49, n. 1, 4 Sep. 2020.