2521-2281 2521-2281 S2521-22812020000100049 10.52379/mcs.v4i1.126 Paraguay Paraguay 00 04 2020 00 04 2020 4 1 49 50 1 2010 2 2 2 109-18 2 2012 10 2 2 273-84 3 2015 71 1 1 15-21 4 2015 37 3 3 105-11 5 2009 19 6 6 1092-9