1. (3) O. H. Duparc: Alfred Wilm and the beginnings of Duralumin, Z. Metallkde, 96(2005), 398-404.
2. (4) H. Y. Hunsicker: History of Precipitation Hardening, The Sorby Centennial Symposium on the History of Metallurgy, ed. by C. S. Smith, Gordon and Breach Science Publishers, (1963), 271.
3. (5) M. B. W. Graham and B. H. Pruitt: R&D for Industry, A Century of Technical Innovation at Alcoa, Cambridge, (1990).
4. (7) D. Hansen and Marie L. V. Gayler: J. Inst. Metals, 26(1921), 321-359.
5. (8) Marie L. V. Gayler: J. Inst. Metals, 28(1922), 213-252.