Bestandslücken
[N=1957,1-2,4,9-10,12; 1958,1-2,5,7-8,10-12; 1959,9-10; 1960,4-6,9-12; 1961,1-2,5-6,10-12; 1961,1-4,6,8; 1963,1,6; 1965,3 ; 1967,2-12; 1968,2-11; 1969,1,8-12; 1970,1,4; 1971,7-10; 1972,1,3-12; 1973; 1974,1,5-10; 1975; 1976,3; 2009,3; 2020,3]