University of Oklahoma. Bureau of Business Research. Economic development series. University of Oklahoma, Bureau of Business Research.
Chicago-referens (17:e uppl.)University of Oklahoma. Bureau of Business Research. Economic Development Series. Norman: University of Oklahoma, Bureau of Business Research.
MLA-referens (8:e uppl.)University of Oklahoma. Bureau of Business Research. Economic Development Series. University of Oklahoma, Bureau of Business Research.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.