Submitted on: 22 July 2018.
Revised on: 17 September 2018.
Accepted on: 15 November 2018.
___________________International Studies of Economics
Submitted on: 11 January 1999.
Revised on: 29 March 1999.
Accepted on: 24 April 1999.
___________________International Studies of Economics
Submitted on: 08 January 2000.
Revised on: 26 February 2000.
Accepted on: 24 March 2000.
___________________International Studies of Economics
http://reply.papertrans.cn/2/145/14437/14437-24.png
http://reply.papertrans.cn/2/145/14437/14437-25.png
http://reply.papertrans.cn/2/145/14437/14437-26.png
Submitted on: 17 September 2010.
Revised on: 25 October 2010.
Accepted on: 26 November 2010.
___________________International Studies of Economics
http://reply.papertrans.cn/2/145/14437/14437-28.png
http://reply.papertrans.cn/2/145/14437/14437-29.png
http://reply.papertrans.cn/2/145/14437/14437-30.png