1Thomas LC, Graham SK, Osteen KD, et al. Comparison of ultrasound and nerve stimulation techniques for intersealene brachial plexus block for shoulder surgery in a residency training environment: a randomized, controlled, observer- blinded trial[J]. Ochsner J, 2011,11 (3) : 246-252.
2Thornton KL, Sacks MD, Hall R, et al. Comparison of 0. 2% ropivacaine and 0. 25 % bupivacaine for axillary braehial plexus blocks in paediatric hand surgery[J]. Paediatr Anaesth, 2003, 13(5) :409-412.