1990-8644 1990-8644 S1990-86442018000300025 Cuba República del Ecuador 00 06 2018 00 06 2018 14 63 25 29

(200 2) (200 2) 307-14 (201 0) (199 7) (200 2) 45-60 (200 5) 3-29 (201 3) (200 4) 36 8 8