62,2=1979; 63,6=1980; 64,2=1981 von: Illinois Library Association: ILA conference proceedings
53,6=1970; 56,4=1973 von: Federal documents
54,5=1972 von: State documents
55,3=1973 von: United Nations documents
56,5=1973 von: Review of the national cancer registration system
53,8=1970/71; 63,9=1980; 64,9=1981/82; 70,5=1986/87 von: Illinois public libraries statistics
68,4=1; 70,7=2 von: Genealogical collections in Illinois
46,8=1963/64; 47,8=1964/65; 48,8=1965/66 von: Statistics of library service in Illinois
49,8=1967; 50,8=1968; 51,8=1968/69; 52,8=1969/70 von: Statistics of library service
54,8=1971/72; 55,8=1972/73; 56,8=1974; 57,9=1975 von: Public library statistics