A. J. Meitei, O. Rubina, L. PKS, J. S. I., D. Ingudum, and M. R. R., “Evaluation of intrathecal bupivacaine alone, bupivacaine with butorphanol and bupivacaine with dexmedetomidine for lower segment caesarean section: a randomized control trial”, Int J Basic Clin Pharmacol, vol. 5, no. 6, pp. 2675–2682, Dec. 2016.