Fentanyl versus tramadol as an adjunct to bupivacaine in ultrasound-guided supraclavicular brachial plexus blockade: pros and cons - Ghazaly, Huda; Eldemrdash, Ayman; Atito, Bahaa; Abdelrheem, Shaimaa; A. Aly, Ahmed (Anaesthesia, Pain & Intensive Care, 2021)