Submitted on: 07 December 2017.
Revised on: 27 February 2018.
Accepted on: 20 April 2018.
___________________Enfoque UTE---UNIV TECNOLOGICA EQUINOCCIAL
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Submitted on: 17 June 2010.
Revised on: 26 August 2010.
Accepted on: 07 September 2010.
___________________Enfoque UTE---UNIV TECNOLOGICA EQUINOCCIAL
Submitted on: 12 August 2002.
Revised on: 13 October 2002.
Accepted on: 24 October 2002.
___________________Enfoque UTE---UNIV TECNOLOGICA EQUINOCCIAL
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Submitted on: 20 March 2011.
Revised on: 14 May 2011.
Accepted on: 28 May 2011.
___________________Enfoque UTE---UNIV TECNOLOGICA EQUINOCCIAL
Submitted on: 28 July 2017.
Revised on: 23 August 2017.
Accepted on: 07 September 2017.
___________________Enfoque UTE---UNIV TECNOLOGICA EQUINOCCIAL
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