Clark, C. (1951). The conditions of economic progress (2d ed. completely rewritten.). Macmillan.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रClark, Colin. The Conditions of Economic Progress. 2d ed. completely rewritten. London: Macmillan, 1951.
एमएलए (9वां संस्करण) प्रशस्ति पत्रClark, Colin. The Conditions of Economic Progress. 2d ed. completely rewritten. Macmillan, 1951.
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