“Theon of Alexandria,” in Encyclopaedia Britannica, Micropaedia, 15th ed., vol. 9, col. 938; “Euclid,” in Encyclopaedia Britannica, Macropaedia, 15th ed., vol. 6, col. 1020; Ellens, Alexandria, p. 44; and Dzielska, Hypatia of Alexandria, pp. 68–69.