2521-2281 2521-2281 S2521-22812020000100047 10.52379/mcs.v4i1.125 Paraguay Paraguay 00 04 2020 00 04 2020 4 1 47 48 1 2014 49 182 182 59-66 2 2019 13 1 1 38-42 3 2018 42 9 9 557-66 4 2019 12 3 3 243-6