Submitted on: 08 July 2005.
Revised on: 21 October 2005.
Accepted on: 06 November 2005.
___________________Electronic Journal of Statistics
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Submitted on: 20 November 2013.
Revised on: 16 March 2014.
Accepted on: 31 March 2014.
___________________Electronic Journal of Statistics
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Submitted on: 14 December 2000.
Revised on: 15 January 2001.
Accepted on: 11 March 2001.
___________________Electronic Journal of Statistics