Volume 13, Issue 5, May 2012, Pages 2133-2137
Volume 12, Issue 11, November 2011, Pages 2995-2999
Volume 12, Issue 11, November 2011, Pages 3101-3105
Volume 10, Issue 6, June 2009, Pages 1067-1070
Volume 9, Issue 4, April 2008, Pages 781-784
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