Submitted on: 19 May 2002.
Revised on: 30 August 2002.
Accepted on: 30 September 2002.
___________________Decisions in Economics and Finance
Submitted on: 19 June 2005.
Revised on: 17 September 2005.
Accepted on: 12 November 2005.
___________________Decisions in Economics and Finance
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Submitted on: 08 August 2005.
Revised on: 01 December 2005.
Accepted on: 07 January 2006.
___________________Decisions in Economics and Finance
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