1. T.A. Wertime: The Coming of the Age of Steel, University of Chicago Press, Chicago, IL, 1962, p. 21.
2. Georg Agricola: De re Metallica, 1556, translation by Herbert C. Hoover and Lou H. Hoover, Dover, New York, NY, 1950.
3. Mathurin Jousse: in The Science of Steel, Cyril Stanley Smith, ed., University of Chicago Press, Chicago, IL, 1968, p. 48.
4. W.C. Roberts-Austen: Phil. Trans. Soc., 1888, vol. A179, pp. 339–50.
5. Max Hanson: Constitution of Binary Alloys, 2nd ed., McGraw-Hill, New York, NY, 1958.