1. W. P. Allis, Conference on Plasma Oscillations, Union Carbide Corporation, Indianapolis, Indiana (1959).
2. Collective Oscillations in a Cold Plasma
3. K. O. Friedrichs and H. Kranzer, “Nonlinear Wave Motion” NYO-6486-VIII, Courant Institute of Mathematical Sciences, New York University (1958).
4. J. Bazer and O. Fleischman, “Propagation of Weak Hydromagnetic Discontinuities,” HM-10, Courant Institute of Mathematical Sciences, New York University (1959).