RT Journal Article SR Electronic T1 Costoclavicular approach to the brachial plexus block: simple or double injection? JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP rapm-2019-100852 DO 10.1136/rapm-2019-100852 A1 Enrique Monzó A1 Admir Hadzic YR 2019 UL http://rapm.bmj.com/content/early/2019/09/28/rapm-2019-100852.abstract AB