Birk. Fostering on the Farm. University of Illinois Press.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBirk. Fostering on the Farm. University of Illinois Press.
एमएलए (9वां संस्करण) प्रशस्ति पत्रBirk. Fostering on the Farm. University of Illinois Press.
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