Blakemore, Colin, and Sheila Jennett. “Great Chain of Being.” The Oxford Companion to the Body, Oxford University Press, 2001. www-oxfordreference-com.ezproxy.library.wwu.edu, http://www.oxfordreference.com/view/10.1093/acref/9780198524038.001.0001/acref-9780198524038-e-433.

Boyer, Carl B. “The Theory of the Rainbow: Medieval Triumph and Failure.” Isis, vol. 49, no. 4, 1958, pp. 378–90. JSTOR.

Lovejoy, Arthur O. The Great Chain of Being: A Study of the History of an Idea. Harvard University Press.

Pynchon, Thomas. Gravity’s Rainbow. Deluxe edition, Penguin Classics, 2006.

Radding, Charles M. “Fortune and Her Wheel: The Meaning of a Medieval Symbol.” Mediaevistik, vol. 5, 1992, pp. 127–38. JSTOR.