Submitted on: 28 October 2012.
Revised on: 14 November 2012.
Accepted on: 28 November 2012.
Portuguese Economic Journal---SPRINGER HEIDELBERG
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Submitted on: 20 April 2009.
Revised on: 09 May 2009.
Accepted on: 31 May 2009.
Portuguese Economic Journal
Submitted on: 26 August 2009.
Revised on: 05 October 2009.
Accepted on: 31 October 2009.
Portuguese Economic Journal---SPRINGER HEIDELBERG