0186-7210 0186-7210 S0186-72102006000100049 10.24201/edu.v21i1.1261 Mexico 00 04 2006 00 04 2006 21 1 49 81

1998 107-35 1997 59 3 3 655-69 1999 5 9 9 1036-57 Batliwala 1994 127-38 2001 6 6 269-80 1999 1977 32 32 513-30 1979 1993 1999 5 9 9 1017-35 1989 89 89 946-9 2003 Minneapolis 2003 271-9 2000 1995 16 6 6 563-76 1985 2001 1999 1971 33 33 624-33 1995 1998 4 4 262-90 1999 2002 2002 55 55 1385-99 IMSS 2000 2003 16 16 2002 2001 1998 2000 Los Ángeles, California 2004 58 58 787-98 1999 61 4 4 947-58 1999 5 9 9 993-1016 2002 1984 1998 5 5 257-76 1994 1990 2001 43 3 3 182-91 2002 34 4 4 178-84 1990 1998 2000 1996 43 43 1792-42 1998 8 2 2 148-57 1996 7 7 129-34 1998 1998 2 1 1 61-73 1998 6 6 57-65 1999 5 9 9 1059-63