1870-4115 1870-4115 S1870-41152008000100225 10.22201/cimsur.18704115e.2008.5.214 Mexico 00 06 2008 00 06 2008 3 5 225 236 1981 90 7-81 1971 1981 98-101 1990 145-69 1978 1 2 2 69-81