1. spatial harmonic traveling-wave amplifier for six millimeters wavelength;Millman;Proc. IRE,1951
2. Traveling-wave tube experiments at millimeter wavelengths with a new easily built space harmonic circuit;Karp;Proc. IRE,1955
3. White, R. M., Birdsall, C. K., and Grow, R. W. Multiple ladder circuits for millimeter wavelength traveling-wave tubes. Proc. Symp. Millimeter Waves, Polytech. Inst. Brooklyn, 1959, pp. 367–402.
4. “Traveling-Wave Tubes.”;Pierce,1950
5. Optical theory of thermal velocity effects in cylindrical beams;Herrmann;J. Appl. Phys.,1958