“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.