Submitted on: 16 October 2009.
Revised on: 07 November 2009.
Accepted on: 16 December 2009.
___________________Econometrics and Statistics---ELSEVIER
Submitted on: 02 December 2017.
Revised on: 23 January 2018.
Accepted on: 12 February 2018.
___________________Econometrics and Statistics---ELSEVIER
Submitted on: 19 July 2014.
Revised on: 15 November 2014.
Accepted on: 19 December 2014.
___________________Econometrics and Statistics---ELSEVIER
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Submitted on: 17 May 2016.
Revised on: 28 June 2016.
Accepted on: 26 August 2016.
___________________Econometrics and Statistics---ELSEVIER
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