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Submitted on: 13 July 2005.
Revised on: 08 October 2005.
Accepted on: 26 October 2005.
___________________JOURNAL OF ECONOMIC LITERATURE
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Submitted on: 01 January 2000.
Revised on: 05 February 2000.
Accepted on: 06 March 2000.
___________________JOURNAL OF ECONOMIC LITERATURE
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Submitted on: 04 June 2001.
Revised on: 24 June 2001.
Accepted on: 14 August 2001.
___________________JOURNAL OF ECONOMIC LITERATURE