Westermann, W. L. (1955). The slave systems of Greek and Roman antiquity. American Philosophical Society.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रWestermann, William Linn. The Slave Systems of Greek and Roman Antiquity. Philadelphia: American Philosophical Society, 1955.
एमएलए (9वां संस्करण) प्रशस्ति पत्रWestermann, William Linn. The Slave Systems of Greek and Roman Antiquity. American Philosophical Society, 1955.
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