1. See for example, “Electrostatic Propulsion“, Staff of the Ramo Wooldridge Research Laboratories, Proceedings of the I.R.E., April, 1960, page 477.
2. H. Mirels and B. M. Rosenblum, “Analysis of One-Dimensional Ion Rocket with Grid Neutralization“, NASA Technical Note D-266, Washington, D.C., March, 1960.