0034-7523 0034-7523 S0034-75232021000100001 Cuba 00 03 2021 00 03 2021 60 1 1 2020 33 2 2 1-9 2 2020 30 20 20 1 3 2020 33 2 2 1-14 4 2020 33 2 2 1-14 5 2020 95 6 6 300-10 6 2020 104 748-51