2236-3459 2236-3459 S2236-34592012000200167 10.1590/S2236-34592012000200009 Brazil 00 09 2012 00 09 2012 16 38 167 198

30 1 1 139-59 3 3 167-75 1 3 3 5 5 93-124 3 9 9 29-44 32 48-64