0138-6557 0138-6557 S0138-65572021000400042 Peru Peru 00 12 2021 00 12 2021 50 4 1 2018 18 56 56 2 2020 9 1 1 213-34 3 2016 55 2 2 38-54 4 2017 61 61 a366 5 2009 29 29 29 a119