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Submitted on: 02 June 2009.
Revised on: 10 September 2009.
Accepted on: 24 September 2009.
___________________Communications for Statistical Applications and Methods
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Submitted on: 02 October 2008.
Revised on: 20 December 2008.
Accepted on: 02 January 2009.
___________________Communications for Statistical Applications and Methods
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Submitted on: 15 November 2007.
Revised on: 20 February 2008.
Accepted on: 21 March 2008.
___________________Communications for Statistical Applications and Methods
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