Holdings
Jg. 14.1986,1-6; 15.1987,1-3 u .6; 16.1988,1,2,6; 17.1989,1-2u.4-6; 18.1990,1-5; 19.1991,1-2u.5; 20.1992,2-3u.6; 21.1993,1,3,6; 22.1994,1-2; 23.1995,1-3u.5; 24.1996,1; 26.1998,2; 30.2002,1; ;31.2003,1- 4; 33.2005,1-4; 35.2007,2; 36.2008,2; 37.2009,2-4; 40.2012,1; 44.2016,1; 45.2017,1-2; 46.2018,1-4;47.2019 fortlaufend