Efficacy of ultrasound-guided bilateral erector spinae plane block for postoperative analgesia in laparoscopic sleeve gastrectomy. A retrospective cohort study . Ann Med Res [Internet]. 2021 May 25 [cited 2025 Apr. 4];27(10):2719-25. Available from: http://annalsmedres.org/index.php/aomr/article/view/990