2215-2636 2215-2636 S2215-26362016000300077 10.15517/rk.v40i3.28886 Costa Rica 00 11 2016 00 11 2016 40 77 84

1990 2011 1998 1987 2014 2012 1951 2009 2010 2013 2008 2003 1998 1990 2006 1989 2013 1991 1996 2003 1988 2011 1996 2000 2013 1961 2011 1996