1. ML no. 469;Sturrock,1957
2. 17th Conf. on Electron Tube Research;Phillips,1959
3. The Ubitron, a high-power traveling-wave tube based on a periodic beam interaction in unloaded waveguide
4. Letter to the Editor;Enderby,1965
5. E.J. Gorn, US Patent 2,591,350, filed April 26, 1947, granted April 1, 1952.