Pattarasiriwong, C., Pongrojpaw, D., Chanthasenanont, A., Lertwutwiwat, S., Bhamarapravatana, K. and Suwannarurk, K. (2018) “Acetaminophen / Tramadol Rectal Suppository for the Relief of Perineal Pain after Normal Vaginal Delivery: A randomized controlled trial”, Thai Journal of Obstetrics and Gynaecology. Bangkok, Thailand, 26(3), pp. 182–189. doi: 10.14456/tjog.2018.23.