RT Journal Article SR Electronic T1 Correction: Cervical plexus and greater occipital nerve blocks: controversies and technique update JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 820 OP 820 DO 10.1136/rapm-2018-100261corr1 VO 44 IS 8 YR 2019 UL http://rapm.bmj.com/content/44/8/820.abstract AB