1. History of the University of Michigan, Ann Arbor, MI, 1966, p. 314.
2. The Michigan Alumnus, October 10, 1925, vol. 31, p. 38.
3. Z. Jeffries:Trans. Am. Soc. Steel Treating, 1928, vol. 13, p. 369.
4. M. E. Shank: ASTM STP 158, 1954, p. 48.
5. A.A. Griffith:Phil. Trans. Roy. Soc, 1920, vol. A221, p. 163.