1. Coupling problems for U(p, q) ladder representations;Anderson,1968
2. Group theoretical discussion of relativistic wave equations;Bargmann,1948
3. The transformation of the electrodynamical equations;Bateman,1910
4. The transformations of coordinates which can be used to transform one physical problem into another;Bateman,1910
5. The principle of relativity in electrodynamics and an extension thereof;Cunningham,1910