Mohamed, A. A., T. A. Radwan, A. S. Wahdan, M. M. Mohammed, and A. K. Salama,  "Effect of bilateral ultrasound-guided erector spinae blocks on postoperative pain and opioid use after lumbar spine surgery: A prospective randomized controlled trial",  Egyptian Journal of Anaesthesia, vol. 37, issue 1, pp. 100-106, 2021.