References | Sampling period |
( | 1984-1988 |
( | 1979-1989 |
( | 1987-1996 |
( | 1996-2004 |
( | 1999-2001 |
( | 1986-2005 |
( | 1998-2008 |
( | 1993-2006 |
( | 2003-2011 |
( | 2009-2014 |
( | 2002-2013 |
( | 1995-2015 |