0138-6557 0138-6557 S0138-65572021000200040 Perú 00 06 2021 00 06 2021 50 2 1 2020 1-9 2 2020 20 1-12 3 2017 14 5 5 545-55 4 2018 1 3 3 367-74 5 1961 6 2020 1-9 7 2020 393-419 8 2020 9 2019 3 4 4 10 2021 39 1 1