1. J. R. Pierce ,Theory and Design of Electron Beams(Van Nostrand Company, Toronto, 1954).
2. V. Ya. Arsenin ,Methods of Mathematic Physics and Special Functions(Nauka, Moscow, 1984), p. 241 (in Russian);
3. A. N. Tikhonov and V. I. Arsenine ,Solution of Ill-Posed Problems(Winston, Washington, D.C., 1977).
4. Simulation of 10 A electron-beam formation and collection for a high current electron-beam ion source
5. The improvement on the falling needle viscometer