Mishra, O., S. Sehrawat, and S. Dey. “To Compare the Effects and Efficacy of 0.5% Hyperbaric Levobupivacaine With Fentanyl Versus 0.5% Hyperbaric Bupivacaine With Fentanyl for Subarachnoid Block in Elderly Patients Undergoing Elective Surgeries”. International Journal of Research in Medical Sciences, vol. 14, no. 10, Sept. 2026, pp. 4579-84, doi:10.18203/2320-6012.ijrms20263526.