2Ivani O, Mereto N, Lampugnani E, et al. Ropivacaine in paediatric surgery : preliminary results. Pardiatr Anaesth, 1998,8:127-129
3Harry WG, Bennett JD, Guha SC. Scalene muscles and the brachial plexus: Anatomical variations and their clinical significance, Lin Anat, 1997, 10: 250-252