A. Atri, A. Gupta, and S. Gulati, “Comparison of Dexmedetomidine and Butorphanol as Adjuvants to Levobupivacaine for Epidural Anaesthesia in Hip and Lower Limb Surgeries: A Randomized Controlled Trial ”, JK Science, vol. 23, no. 4, pp. 195–199, Oct. 2021.