2528-79072528-7907S2528-7907202000020019110.36097/rsan.v1i39.1258EcuadorEcuadorEcuador0006202000062020391912022003200510(24)93-12320052361948Volume 11967201220012004200420081996199920071990201632(9945-60198420152011200220082007198920141520102004Villafañe y Asociados Consultores2015