1809-3876 1809-3876 S1809-38762017000300575 10.23925/1809-3876.2017v15i3p575-593 Spain Spain 00 07 2017 00 07 2017 15 3 575 593

60 5 5 497-511 13 47-67 30 2 2 161-71 9 1 1 46-64 7-30