Volume 15, Issue 19, December 2014, Pages 8367-8370
Volume 14, Issue 4, April 2013, Pages 2295-2299
Volume 13, Issue 1, January 2012, Pages 371-375
Volume 11, Issue 4, April 2010, Pages 1099-1105
Volume 11, Issue 3, March 2010, Pages 689-696