González Cárdenas, Víctor Hugo, et al. “Remifentanil Vs. Epidural Analgesia for the Management of Acute Pain Associated With Labour. Systematic Review and Meta-Analysis”. Colombian Journal of Anesthesiology, vol. 42, no. 4, Oct. 2014, pp. 281-94, https://www.revcolanest.com.co/index.php/rca/article/view/243.