Submitted on: 24 October 2003.
Revised on: 29 November 2003.
Accepted on: 15 December 2003.
Revista Economia---PONTIFICIA UNIV CATOLICA PERU
Submitted on: 04 August 2011.
Revised on: 26 August 2011.
Accepted on: 13 September 2011.
NULL
Submitted on: 23 December 2018.
Revised on: 28 January 2019.
Accepted on: 10 February 2019.
NULL
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Submitted on: 22 May 1998.
Revised on: 30 June 1998.
Accepted on: 12 July 1998.
NULL
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