1990-8644 1990-8644 S1990-86442021000300021 Ecuador 00 06 2021 00 06 2021 17 80 21 27

2020 20 27 27 1-11 2018 2 2 2 53-8 2020 39 2 2 2019 40 2 2 161-70 2010 34 71 71 11-31 2020 8 2 2 1-22 2019 38 1 1 1-14 2014 2020 International Organization for Standardization 2015 2019 2019 27 2 2 328-42 2019 11 3 3 61-71 2012 21 3 3 312-7 2018 9 2 2 201-18 2019 11 2 2 312-22