Md Nishat Akhtar, S. Ahmad, and I. Ilahi. “Intrathecal Isobaric Levobupivacaine Versus Isobaric Ropivacaine for Infra-Umbilical Surgeries”. Academia Anesthesiologica International, Vol. 5, no. 1, July 2020, pp. 191-94, https://aijournals.com/index.php/aan/article/view/2204.