A comparative study of the effect of intrathecal tramadol and buprenorphine used as adjuvants to hyperbaric bupivacaine for postoperative analgesia in infraumbilical surgeries - Siddiq, Sana; Asad, Naila; Rehman, Abaid; Ali, Maqsood; Khalid, Hafiz M Usman; Butt, Zulqarnain (Anaesthesia, Pain & Intensive Care, 2019)