Dimmiti Dinesh Raja, et al. “Efficacy of Intrathecal Nalbuphine Over Fentanyl As Adjuvant With Ropivacaine in Lower Abdominal and Lower Limb Surgeries”. IAR Journal of Medicine and Surgery Research, vol. 3, no. 3, June 2020, pp. 14-21, doi:10.47310/iarjmsr.2022.V03i03.04.