Patel, A. S., and A. V. Patel. “Comparative Analysis of Efficacy and Haemodynamic Response Between Intrathecal Hyperbaric 0.5% Bupivacaine With Isobaric 0.75% Ropivacaine Utilizing Fentanyl As Adjuvant in Subjects Undergoing Umbilical Surgeries”. Academia Anesthesiologica International, Vol. 7, no. 1, June 2022, pp. 8-10, https://aijournals.com/index.php/aan/article/view/2338.