Bestandslücken
[N=1966,1-5,8-10,12; 1967,2,4-7; 1968-1970; 1971,3-4; 1972-1975; 1976,1,3-4; 1977; 1978,1,4,5; 1979; 19801-3,5-6 ;1981; 1982,1,3-6;1983,1,3,5; 1984,1,3; 1985,1; 1986,4; 1987,1-3; 1988,1-3; 1989,1; 1990,2-4; 1992,1-3; 1993,1-2; 1994,3-4; 1995; 1996,3]