1. A bibliography and summary of this work is to be found in the article by James Serrin,Handbuch der Physik(Springer-Verlag, Berlin, Germany, 1959), Bd VIII∕1, Pp. 145–150, 203–206.
2. The Electrodynamics of Material Media
3. The derivation of the equations of motion of an ideal fluid by Hamilton's principle
4. J. von Neumann, in a memorandum addressed to O. Veblen, dated March 26, 1945, conjectured that the difficulty of solving the hydrodynamic equations arises, not from their nonlinear character, but from the lack of a variation principle. This memorandum is to be published in the collection of von Neumann’s papers which is being prepared by A. H. Taub.
5. See reference 1, p. 161.