Effects of ketamine hydrochloride (preservative free) and fentanyl citrate added to low dose hyperbaric bupivacaine for sub-arachnoid block in lower uterine caesarian section – a comperative study. (2014). Journal of the Bangladesh Society of Anaesthesiologists, 24(2), 53-59. https://doi.org/10.3329/jbsa.v24i2.19802