1990-8644 1990-8644 S1990-86442020000500215 Ecuador Ecuador 00 10 2020 00 10 2020 16 76 215 220

2009 391-424 2009 2004 23 7-20 2009 2010 49 1 1 32-61 2010 México 2016 2011 2010 2012 2009 2012 8 2003 5 2010 16 5-30 2011 8 2 2 61-76