Kravis, I. B. (1975). A system of international comparisons of gross product and purchasing power. Johns Hopins University Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रKravis, Irving B. A System of International Comparisons of Gross Product and Purchasing Power. Johns Hopins University Press, 1975.
एमएलए (9वां संस्करण) प्रशस्ति पत्रKravis, Irving B. A System of International Comparisons of Gross Product and Purchasing Power. Johns Hopins University Press, 1975.
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