European Commission. (1999). EU focus on clean air. European Communities.
Chicago-čujuhus (17. p.)European Commission. EU Focus on Clean Air. Luxemburgo: European Communities, 1999.
MLA-čujuhus (9. p.)European Commission. EU Focus on Clean Air. European Communities, 1999.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.