Submitted on: 06 February 2006.
Revised on: 04 April 2006.
Accepted on: 27 April 2006.
___________________Empirical Economics---PHYSICA-VERLAG GMBH & CO
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Submitted on: 26 September 2007.
Revised on: 17 November 2007.
Accepted on: 20 December 2007.
___________________Empirical Economics---PHYSICA-VERLAG GMBH & CO
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Submitted on: 24 October 2009.
Revised on: 15 January 2010.
Accepted on: 23 February 2010.
___________________Empirical Economics---PHYSICA-VERLAG GMBH & CO
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Submitted on: 26 October 2007.
Revised on: 30 December 2007.
Accepted on: 17 February 2008.
___________________Empirical Economics---PHYSICA-VERLAG GMBH & CO
Submitted on: 11 April 2004.
Revised on: 05 June 2004.
Accepted on: 15 June 2004.
___________________Empirical Economics---PHYSICA-VERLAG GMBH & CO
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