Shafa, A., Hashemi, S., Heidari, S., & Talebi, Z. (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