1409-3871 1409-3871 S1409-38712017000200261 10.15517/lank.v17i2.30159 Ecuador Ecuador USA 00 08 2017 00 08 2017 17 2 261 278

2011 18 165-7 2004 7 1 1 42-7 2011 11 9-14 1986 15 1990 38 1991 39 2000 79 2002 88 2016 69 161-8