Butler-Fernández, Krystal M., Leyda Morales-Arocho, and Elsa Pedro-Gutiérrez. “Evaluation of the Timing of Opioid Administration: A Pilot Study”. Puerto Rico Health Sciences Journal 42, no. 1 (March 6, 2023): 77–80. Accessed January 8, 2026. https://prhsj.rcm.upr.edu/index.php/prhsj/article/view/2855.