Choi, Stephen Evidence Base for the Use of Ultrasound for Upper Extremity Blocks: 2014 Update. [electronic resource] - Regional anesthesia and pain medicine - 242-50 p. digital Publication Type: Journal Article; Review ISSN: 1532-8651 Standard No.: 10.1097/AAP.0000000000000155 doi Subjects--Topical Terms: Brachial Plexus Block--methodsEvidence-Based Medicine--methodsHumansRandomized Controlled Trials as Topic--methodsUltrasonography, Interventional--methodsUpper Extremity--diagnostic imaging