Submitted on: 28 January 2006.
Revised on: 02 April 2006.
Accepted on: 19 April 2006.
___________________Economics of Transportation---ELSEVIER
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Submitted on: 13 April 2014.
Revised on: 12 July 2014.
Accepted on: 25 July 2014.
___________________Economics of Transportation---ELSEVIER
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Submitted on: 03 June 2010.
Revised on: 07 August 2010.
Accepted on: 10 September 2010.
___________________Economics of Transportation---ELSEVIER
Submitted on: 16 November 2002.
Revised on: 09 December 2002.
Accepted on: 22 January 2003.
___________________Economics of Transportation---ELSEVIER
Submitted on: 29 April 2019.
Revised on: 18 July 2019.
Accepted on: 06 September 2019.
___________________Economics of Transportation---ELSEVIER
Submitted on: 01 December 2001.
Revised on: 06 March 2002.
Accepted on: 14 April 2002.
___________________Economics of Transportation---ELSEVIER
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Submitted on: 26 March 2008.
Revised on: 03 May 2008.
Accepted on: 25 June 2008.
___________________Economics of Transportation---ELSEVIER