Organization of Petroleum Exporting Countries. World oil outlook 2011.
Chicago-čujuhus (17. p.)Organization of Petroleum Exporting Countries. World Oil Outlook 2011.
MLA-čujuhus (9. p.)Organization of Petroleum Exporting Countries. World Oil Outlook 2011.
Muitte dárkkistit čujuhemiid riektatvuođa, ovdal go geavahat daid iežat deavsttas.