0012-7353 0012-7353 S0012-73532018000400269 10.15446/dyna.v85n207.71658 Ecuador 00 12 2018 00 12 2018 85 207 269 277

[1] 1951 13 1 1 65-82 [2] 1967 16 4 4 500-5 [3] 2006 XII 30 30 155-60 [4] 2008 29 4 4 420-8 [5] 2009 24 2 2 93-104 [6] 2017 90-8 [7] 2011 01 3 3 147-54 [8] 2012 15 [9] 2014 1713-23 [10] 1972 114 2 2 139-62 [11] 1968 [12] 2014 237 1 1 164-76 [13] 2017 134 1-11 [14] 2018 151 605-21 [15] 2008 [16] 2012 1a [17] CEN 2010 [18] CEN 2007 [19] 2006