1. A 10.1 mathshistory.st-andrews.ac.uk/Biographies/Abel/
2. A 10.2 Interview of Eugene Wigner by Charles Weiner and Jagdish Mehra on 1966 November 30, Niels Bohr Library & Archives, American Institute of Physics, College Park, MD USA, www.aip.org/history-programs/niels-bohr-library/oral-histories/4964
3. A 10.3 www.math.uni-goettingen.de/historisches/weyl.html
4. A 10.4 http://en.wikipedia.org/wiki/Yang–Mills_theory
5. A 10.5 www.worldscientific.com/page/10308-chap01