Prasad G. V., K., & Sharma, V. J. (2019). A comparative study of hemodynamic changes and adverse effects of intrathecal bupivacaine with fentanyl and intrathecal bupivacaine with clonidine in infra-umbilical abdominal and lower limb surgery. International Surgery Journal, 6(11), 4048–4055. https://doi.org/10.18203/2349-2902.isj20195121