Shafa, Amir, Seyedjalal Hashemi, Seyedmorteza Heidari, and Zeynab Talebi. 2018. “Comparison of Pre-Emptive Analgesic Effect of Rectal Ketamine and Caudal Bupivacaine in Pediatric Lower Abdominal Surgery”. Iranian Journal of Pediatric Surgery 4 (2):61-70. https://doi.org/10.22037/irjps.v4i2.22280.