Mc Donnell, MD, MB, C., Pehora, MN, C., & Crawford, MBBS, M. W. (2012). PCA-derived factors that may be predictive of postoperative pain in pediatric patients: A possible role for the PCA ratio. Journal of Opioid Management, 8(1), 39–44. https://doi.org/10.5055/jom.2012.0094