Eurobarometer: http://zacat.gesis.org/webview/index.jsp?object=http://zacat.gesis.org/obj/fCatalog/Catalog5
ISSP: http://zacat.gesis.org/webview/index.jsp?object=http://zacat.gesis.org/obj/fCatalog/Catalog5
European Social Survey: http://ess.tk.mta.hu/adatbazis/adatbazisok/
TÁRKI Adatbank: http://www.tarki.hu/hu/services/da/index.html