1. Kaufman, H. R., “An Ion Rocket with an Electron-Bombardment Ion Source, “ NASA TN D-585, Jan. 1961.
2. Kaufman, H. R., “One-Dimensional Analysis of Ion Rockets,“ NASA TN D-261, March 1960.
3. Mirels, H. and Rosenbaum, B. M., “Analysis of One-Dimensional Ion Rocket with Grid Neutralization, “ NASA TN D-266, March 1960.