Sahoo, Swagatika, et al. “Comparison Between Levobupivacaine and Levobupivacaine With Clonidine in Erector Spinae Plane Block in Patients Undergoing Open Cholecystectomy: A Prospective Randomized Double Blinded Study”. JK Science: Journal of Medical Education & Research, vol. 27, no. 2, Apr. 2025, pp. 113-7, https://journal.jkscience.org/index.php/JK-Science/article/view/353.