Submitted on: 28 September 2006.
Revised on: 14 December 2006.
Accepted on: 04 February 2007.
___________________Agricultural and Food Economics
Submitted on: 24 July 2003.
Revised on: 16 October 2003.
Accepted on: 27 November 2003.
___________________Agricultural and Food Economics
Submitted on: 15 November 2005.
Revised on: 13 January 2006.
Accepted on: 04 March 2006.
___________________Agricultural and Food Economics
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Submitted on: 19 September 2005.
Revised on: 12 October 2005.
Accepted on: 24 October 2005.
___________________Agricultural and Food Economics
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