References for Callippus

  1. J S Kieffer, Biography in Dictionary of Scientific Biography (New York 1970-1990).
    See THIS LINK.
  1. Calendar, Encyclopaedia Britannica.
  2. T L Heath, Aristarchus of Samos (Oxford, 1913).
  3. T L Heath, A History of Greek Mathematics (2 Vols.) (Oxford, 1921).
  4. O Neugebauer, A history of ancient mathematical astronomy (New York, 1975).
  1. B L van der Waerden, Greek astronomical calendars. II. Callippos and his calendar, Arch. Hist. Exact Sci. 29 (2) (1984), 115-124.