Comparison of balloon angioplasty and papaverine infusion for the treatment of vasospasm following aneurysmal subarachnoid hemorrhage - Elliott, JP; Newell, DW; Lam, DJ; Eskridge, JM; Douville, CM; Le Roux, PD; Lewis, DH; Mayberg, MR; Grady, MS; Winn, HR (J Neurosurg, 1998)