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Submitted on: 08 December 2010.
Revised on: 20 March 2011.
Accepted on: 01 May 2011.
___________________JOURNAL OF COMPUTER AND SYSTEMS SCIENCES INTERNATIONAL
Submitted on: 20 November 2010.
Revised on: 24 December 2010.
Accepted on: 06 January 2011.
___________________JOURNAL OF COMPUTER AND SYSTEMS SCIENCES INTERNATIONAL
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