The Chaucer Review: An Indexed Bibliography (Vols. 1-30)

Conlee, John W. "The Meaning of Troilus' Ascension to the Eighth Sphere." 7 (1972): 27-36.
The stanzas which describe Troilus in the spheres are connected to the classical and medieval motif of a celestial journey. Chaucer integrates Greek, Roman, and Christian ideas of immortality into Troilus and Criseyde by varied use of the number eight and its numerological connotations in medieval thought. Troilus ascends to the eighth sphere, and the number eight indicates "completion of a cycle . . . purification; and immortality, eternity, and eternal salvation" (34). Thus Chaucer can, by introducing numerology, prepare the way for the section on Christian love that ends the poem.

Voigts, Linda Ehrsam. "The Latin Verse and Middle English Prose Texts on the Sphere of Life and Death in Harley 3719." 21 (1986): 291-306.
According to medieval thinking, the universe was built on a numerical system. Understanding this system gave people the power to predict various events, including whether a person would live or die as the result of a certain illness. The Sphere of Life and Death gives the mathematical formulas and a chart to predict the outcome of a patient. Comparison to other manuscripts suggests that the Sphere of Life and Death is connected to "a fifteenth-century scientific and medical compendium of English origin" (297). The verse accompanying the Sphere also seems to have a source in the Anglo-Saxon tradition. Other studies of Middle English prose neglect to mention the works which follow this tradition. The text of the Sphere of Life and Death is reprinted here.