Submitted on: 10 February 2007.
Revised on: 02 March 2007.
Accepted on: 25 March 2007.
Seoul Journal of Economics---SEOUL NATL UNIV, INST ECONOMIC RESEARCH
http://reply.papertrans.cn/3/279/27845/27845-32.png
http://reply.papertrans.cn/3/279/27845/27845-33.png
Submitted on: 30 November 1999.
Revised on: 09 December 1999.
Accepted on: 15 December 1999.
Seoul Journal of Economics---SEOUL NATL UNIV, INST ECONOMIC RESEARCH
http://reply.papertrans.cn/3/279/27845/27845-35.png
http://reply.papertrans.cn/3/279/27845/27845-36.png