Lopera-Velásquez, Luz María, and Carlos Restrepo-Garcés. “Ultrasound and Nerve Stimulation-Guided Axillary”. Colombian Journal of Anesthesiology, vol. 44, no. 1, Jan. 2016, pp. 30-35, https://www.revcolanest.com.co/index.php/rca/article/view/64.