0379-3982 0379-3982 S0379-39822017000500030 10.18845/tm.v30i5.3218 Costa Rica 00 12 2017 00 12 2017 30 30 34

1997 25 3389-402 2005 29 211-27 2003 6 557-70 1999 41 95-8 1970 48 443-53 1970 147 195-7 2007 7 13-8