Simmel, G. (1977). The problems of the Philosophy of History: An epistemological essay. The Free Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रSimmel, Georg. The Problems of the Philosophy of History: An Epistemological Essay. The Free Press, 1977.
एमएलए (9वां संस्करण) प्रशस्ति पत्रSimmel, Georg. The Problems of the Philosophy of History: An Epistemological Essay. The Free Press, 1977.
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