Linh, Đỗ P. and Tú, N.H. 2021. Evaluation of ultrasound-assisted thoracic epidural anesthesia in reducing postoperative pain in patients undergoing upper abdominal surgery: A randomized controlled trial. Journal of Medical Research. 138, 2 (May 2021), 140-147. DOI:https://doi.org/10.52852/tcncyh.v138i2.88.