Submitted on: 20 August 2002.
Revised on: 16 December 2002.
Accepted on: 20 January 2003.
___________________EUROPEAN REVIEW OF AGRICULTURAL ECONOMICS
http://reply.papertrans.cn/1/94/9384/9384-32.png
http://reply.papertrans.cn/1/94/9384/9384-33.png
Submitted on: 06 June 2015.
Revised on: 24 July 2015.
Accepted on: 29 August 2015.
___________________EUROPEAN REVIEW OF AGRICULTURAL ECONOMICS
http://reply.papertrans.cn/1/94/9384/9384-35.png
http://reply.papertrans.cn/1/94/9384/9384-36.png