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Betten DP, Cantrell FL, Thomas SC, Williams SR, Clark RF.Betten DP, et al. Among authors: clark rf.Ann Emerg Med. 2007 Sep;50(3):272-9. doi: 10.1016/j.annemergmed.2006.11.010. Epub 2007 Jan 8.Ann Emerg Med. 2007.PMID: 17210206