Submitted on: 01 May 2018.
Revised on: 29 June 2018.
Accepted on: 19 August 2018.
___________________ENVIRONMENTAL & RESOURCE ECONOMICS
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Submitted on: 03 November 2010.
Revised on: 26 January 2011.
Accepted on: 21 February 2011.
___________________ENVIRONMENTAL & RESOURCE ECONOMICS
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