1. J. Barnes, Early Greek Philosophy, 2nd edn. (Penguin Books, London, 2001), Part II
2. J. Barnes, The Presocratic Philosophers (Routledge, London, New York, 1982), Chap. X
3. Aristotle, Physics, in Great Books of the Western World, vol. 7, ed. by M.J. Adler (Encyclopedia Britannica, Chicago, 1993)
4. V. Petkov, Relativity and the Nature of Spacetime, 2nd edn. (Springer, Heidelberg, 2009)
5. G. Galileo, Dialogue Concerning the Two Chief World Systems—Ptolemaic and Copernican, 2nd edn. (University of California Press, Berkeley, 1967). The Second Day