http://reply.papertrans.cn/2/165/16412/16412-31.png
http://reply.papertrans.cn/2/165/16412/16412-32.png
Submitted on: 03 October 2017.
Revised on: 26 January 2018.
Accepted on: 23 March 2018.
___________________Journal of Econometrics---ELSEVIER SCIENCE SA
http://reply.papertrans.cn/2/165/16412/16412-34.png
Submitted on: 07 September 1999.
Revised on: 27 December 1999.
Accepted on: 26 January 2000.
___________________Journal of Econometrics---ELSEVIER SCIENCE SA
http://reply.papertrans.cn/2/165/16412/16412-36.png