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Submitted on: 18 June 2007.
Revised on: 02 September 2007.
Accepted on: 30 September 2007.
___________________JOURNAL OF PUBLIC ECONOMICS---ELSEVIER SCIENCE SA
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Submitted on: 04 January 2007.
Revised on: 02 May 2007.
Accepted on: 04 June 2007.
___________________JOURNAL OF PUBLIC ECONOMICS---ELSEVIER SCIENCE SA
Submitted on: 09 August 2001.
Revised on: 19 September 2001.
Accepted on: 21 October 2001.
___________________JOURNAL OF PUBLIC ECONOMICS---ELSEVIER SCIENCE SA
Submitted on: 12 November 2007.
Revised on: 03 February 2008.
Accepted on: 01 April 2008.
___________________JOURNAL OF PUBLIC ECONOMICS---ELSEVIER SCIENCE SA
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Submitted on: 11 December 2002.
Revised on: 12 March 2003.
Accepted on: 30 April 2003.
___________________JOURNAL OF PUBLIC ECONOMICS---ELSEVIER SCIENCE SA