Submitted on: 12 September 2015.
Revised on: 05 October 2015.
Accepted on: 12 November 2015.
___________________Economics and Business Review---SCIENDO
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Submitted on: 12 December 2006.
Revised on: 09 February 2007.
Accepted on: 09 April 2007.
___________________Economics and Business Review---SCIENDO
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Submitted on: 16 August 2000.
Revised on: 06 September 2000.
Accepted on: 29 October 2000.
___________________Economics and Business Review---SCIENDO
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