Sofia Jaswal, Rashi Sarna, Richa Saroa, and Sanjeev Palta, “Determination of Tramadol as an Adjuvant to Ropivacaine in Utrasound Guided Erector Spinae Plane Block for Postoperative Analgesia after Sternotomy”, RDMMR-V7, pp. 163–169, Oct. 2021.