Research centers directory.

1960; 1979; 1982-1983; 1984-1985; 1986 v.1; 1986 v.2; 1987 pt.1; 1987 pt.2; 1987 v.1; 1987 v.2; 1988 v.1; 1988 v.2; 1989 v.1; 1989 v.2; 1990 v.1; 1991 v.1; 1992 v.1; 1993 v.1; 1993 v.2; 1994 v.1; 1995 v.1; 1995 v.2; 1996 v.1; 1996 v.2; 1996-1997 v.1; 1996-1997 v.2; 1997 v.1; 1997 v.2; 1998 v.1; 1998 v.2; 1999 v.1; 1999 v.2; 1999-2000 v.1; 1999-2000 v.2; 2000 v.1; 2000 v.2; 2001 v.1; 2001 v.2; 2002 28th ed. v.1; 2002 28th ed. v.2; 29th ed. 2002 v.2; 2002 29th ed. v.2; 2003 v.2; 2007 v.1; 2007 v.2; 2008:v.1; 2008:v.2; 1960 Suppl.