Ardrey, R. (1970). The social contract: A personal enquiry into the evolutionary sources of order and disorder. Collins.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रArdrey, Robert. The Social Contract: A Personal Enquiry into the Evolutionary Sources of Order and Disorder. London: Collins, 1970.
एमएलए (9वां संस्करण) प्रशस्ति पत्रArdrey, Robert. The Social Contract: A Personal Enquiry into the Evolutionary Sources of Order and Disorder. Collins, 1970.
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