Submitted on: 25 May 2005.
Revised on: 01 August 2005.
Accepted on: 09 September 2005.
___________________International Journal of Ecological Economics & Statistics
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Submitted on: 15 December 2009.
Revised on: 18 March 2010.
Accepted on: 17 April 2010.
___________________International Journal of Ecological Economics & Statistics
Submitted on: 15 July 1998.
Revised on: 22 August 1998.
Accepted on: 29 September 1998.
___________________International Journal of Ecological Economics & Statistics
Submitted on: 29 November 2012.
Revised on: 31 January 2013.
Accepted on: 24 March 2013.
___________________International Journal of Ecological Economics & Statistics