In 1992, four polish libraries took the decision to buy integrated library system VTLS. Maintaining of the modern online catalogue under control of authority files seemed to be to great challenge for one library, so that co-operation between librariesappeared as a must. The representatives of libraries made a great pressure to establish the independent unit. It was called "Centre for Formats and Authority File" and established at the Warsaw University Library in 1996. There are two: Section for Formats and Name Authority, Section for Subject Headings Language and Subject Authority File KABA. At the present the Centre serves as a source of authority records for 20 libraries in country and co-operates with libraries using the other integrated systems (e.g. Horizon). Since January 1998, the representatives of libraries - VTLS and Horizon users and National Library in Warsaw have begun the co-operation in preparing to create the National Union Catalogue "NUKat".