1990-8644 1990-8644 S1990-86442020000600466 Cuba Ecuador 00 12 2020 00 12 2020 16 77 466 474

2013 2017 22 75 75 1021-44 Ecuador. Ministerio de Educación 2014 2017 9 4 4 162-7 2020 26 1 1 166-7 2019 45 200049 200049 5-6 2018 2007 2008 2018 2018 2018