Limbunjerd K. The effects of additive intrathecal fentanyl on time to first analgesic requirement in unilateral inguinal hernia surgery. Reg11MedJ [internet]. 2022 Dec. 21 [cited 2026 Sep. 19];36(3). available from: https://he02.tci-thaijo.org/index.php/Reg11MedJ/article/view/259225