Volume 13, Issue 2, February 2012, Pages 473-477
Volume 12, Issue 12, December 2011, Pages 3207-3212
Volume 12, Issue 10, October 2011, Pages 2741-2745
Volume 12, Issue 8, August 2011, Pages 2065-2068
Volume 12, Issue 7, July 2011, Pages 1771-1776
Volume 12, Issue 1, January 2011, Pages 149-151
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