Buettner, D. (2021). The Blue Zones challenge: A 4-week plan for a longer, better life. National Geographic Society.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBuettner, Dan. The Blue Zones Challenge: A 4-week Plan for a Longer, Better Life. [Washington, D.C.]: National Geographic Society, 2021.
एमएलए (8वां संस्करण) प्रशस्ति पत्रBuettner, Dan. The Blue Zones Challenge: A 4-week Plan for a Longer, Better Life. National Geographic Society, 2021.
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