1. History of electrostatic recording;Carlson,1965
2. Charged pigment xerography;Scharfe,1975
3. Photogeneration and transport processes in Photoconductors for electrophotography;Pai,1980
4. W.E. Bixby, U.S. Patent 2,970,906, (1961).
5. Onsager mechanism of photogeneration in amorphous selenium