Interscalene brachial plexus anesthesia and analgesia for open shoulder surgery: a randomized, double-blinded comparison between levobupivacaine and ropivacaine.
Casati A, Borghi B, Fanelli G, Montone N, Rotini R, Fraschini G, Vinciguerra F, Torri G, Chelly J. Anesth Analg. 2003 Jan; 96(1):253-9, table of contents.