1659-3820 1659-3820 S1659-38202018000200045 10.18845/rc.v27i2.4006 Ecuador 00 12 2018 00 12 2018 27 2 45 58

2016 2015 2014 2016 9 1 1 1-17 2007 2015 19 2 2 2016 1994 2014 21 42 42 . 45-53 2015 2013 6 2013 28 2015 2014 324