1. The Early Development of Electron Lenses and Electron Microscopy;Ruska,1980
2. Charging-up potential and secondary emission of bodies irradiated by electrons;Knoll;Z. Tech. Phys.,1935
3. The electron scanning microscope: Theoretical principles;von Ardenne;Z. Phys.,1938
4. The electron scanning microscope: Practical realization;von Ardenne;Z. Techn. Phys.,1938
5. The history and future of the scanning electron microscope;Wells,1987