CHHAJED, G. M. A Comparative Study of Epidural Ropivacaine with Fentanyl versus Bupivacaine with Fentanyl for Postoperative Analgesia in Elective Lower Abdominal and Lower Limb Surgeries. Journal of Biomedical and Pharmaceutical Research, v. 5, n. 3, 30 Jun. 2016.