Polley L S
Department of Anesthesiology, Division of Obstetric Anesthesiology, Women's Hospital, University of Michigan Health System, Ann Arbor, Michigan 48109-5278, USA.
Int J Obstet Anesth. 2008 Apr;17(2):149-52. doi: 10.1016/j.ijoa.2007.11.006. Epub 2008 Mar 4.