1. R.W. Grow, Dept. of E.E, University of Utah, private communication.
2. O.P. Gandhi, Dept. of E E, University of Utah, private communication.
3. G.R. Fowles, Dept. of Physics, University of Utah, private communication.
4. Heating with microwaves;Püschner,1964
5. Stimulated Emission of Bremsstrahlung