Não informado. (1971). Bulletin of Economic Research. University of Hull, Department of Economics.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Bulletin of Economic Research. Hull, Inglaterra: University of Hull, Department of Economics, 1971.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Bulletin of Economic Research. University of Hull, Department of Economics, 1971.
चेतावनी: ये उद्धरण हमेशा 100% सटीक नहीं हो सकते हैं.