Submitted on: 16 January 2011.
Revised on: 27 April 2011.
Accepted on: 26 May 2011.
___________________International Journal of Mathematical Engineering and Management Sciences
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Submitted on: 24 January 2007.
Revised on: 13 March 2007.
Accepted on: 10 May 2007.
___________________International Journal of Mathematical Engineering and Management Sciences
Submitted on: 14 December 2014.
Revised on: 08 March 2015.
Accepted on: 01 April 2015.
___________________International Journal of Mathematical Engineering and Management Sciences
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Submitted on: 28 January 2013.
Revised on: 03 May 2013.
Accepted on: 09 June 2013.
___________________International Journal of Mathematical Engineering and Management Sciences