1990-8644 1990-8644 S1990-86442020000600391 Ecuador 00 12 2020 00 12 2020 16 77 391 398

1980 2009 2014 2011 25 1 1 82-94 2001 51 4 4 321-31 2018 2006 33 226-31 2008 65 6 6 502-18 2018 2016 2016 15 44 44 209-21 2018 2017 2008 28 3 3 9-19