Convention on Social Security that provides the principle of good cooperation between liaison bodies (Slovenia – Croatia)
European regulation and bilateral agreement on social security that provides posting of workers (Slovenia – Croatia – Austria – Italy – Hungary)
Interstate agreements on social security (Slovenia – Bosnia and Herzegovina – Croatia – Macedonia – Serbia)
The Danube River Network of Protected Areas (Slovakia – Austria – Bulgaria – Croatia – Germany – Hungary – Romania – Hungary – Serbia – Ukraine)
Agreement on Recognition of School report cards, Diplomas and Higher Education Levels acquired (Croatia – Hungary)