2477-9199 2477-9199 S2477-91992020000200176 10.26807/cav.v0i09.315 Ecuador 00 12 2020 00 12 2020 9 176 189

1980 1982 1983 1982 1980 1982 2020 53-74 2020 75-86 1965 2020 133-58 2001 2020 433-56 1990 2020 327-55 2020 201-63