1. W. Glaser, Grundlagen der Elektronenoptik (Springer, Wien, 1952)
2. P.W. Hawkes, E. Kasper, Principles of Electron Optics, vols. 1–3 (Academic, London, 1995)
3. M.R. Spiegel, Vector Analysis (McGraw-Hill, New York, 1974)
4. F. Ollendorff, Potentialfelder der Elektrotechnik (Springer, Berlin, 1932)
5. E. Munro, in Image Processing and Computer-Aided Design in Electron Optics, ed. by P.W. Hawkes (Academic, London, 1978), pp. 284–323