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Submitted on: 09 October 2006.
Revised on: 07 November 2006.
Accepted on: 27 December 2006.
___________________Journal of Mathematical Inequalities
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Submitted on: 01 February 2012.
Revised on: 18 March 2012.
Accepted on: 08 April 2012.
___________________Journal of Mathematical Inequalities
Submitted on: 09 August 2010.
Revised on: 23 September 2010.
Accepted on: 03 November 2010.
___________________Journal of Mathematical Inequalities