North Sea Task Force. (1993). North sea quality status report 1993. Olsen and Olsen.
Chicago-čujuhus (17. p.)North Sea Task Force. North Sea Quality Status Report 1993. Fredensborg: Olsen and Olsen, 1993.
MLA-čujuhus (9. p.)North Sea Task Force. North Sea Quality Status Report 1993. Olsen and Olsen, 1993.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.