1. Monthly Bulletin, AIME, July 1917, no. 127, pp. xv–xxxiii.
2. G.K. Burgess:Memoirs, vol. XXI, no. 7, pp. 1–6, National Academy of Sciences, 1926.
3. William Campbell:Science, 1922, New Series, vol. LV, pp. 631–33.
4. Maxwell Gensamer:The Sorby Centennial Symposium on the History of Metallurgy, Edited by C. S. Smith. Met. Soc. Conferences, no. 27, pp. 59–66. Gordon and Breach Science Publishers, New York, 1965.
5. Ibid.,, 1965 p. 59.