Depth of cervical plexus block and phrenic nerve blockade: a randomized trial
Mathias Opperer, Reinhard Kaufmann, Matthias Meissnitzer, Florian K Enzmann, Christian Dinges, Wolfgang Hitzl, Jürgen Nawratil, Andreas Koköfer
Regional Anesthesia & Pain Medicine Apr 2022, 47 (4) 205-211; DOI: 10.1136/rapm-2021-102851