1390-8596 1390-8596 S1390-85962017000200053 10.17163/lgr.n25.2017.05 Ecuador Ecuador 00 08 2017 00 08 2017 25 1 53 61

2009 2008 2008 1998 2011 1964 2004 2002 2007 2010 1996 2013 2009 2006