Macdougall, J. D. (2013). Frozen earth: The once and future story of ice ages. University of California Press.
Lua i Stíl Chicago (17ú heag.)Macdougall, J. D. Frozen Earth: The Once and Future Story of Ice Ages. Berkeley: University of California Press, 2013.
Lua MLA (9ú heag.)Macdougall, J. D. Frozen Earth: The Once and Future Story of Ice Ages. University of California Press, 2013.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.