1. For an excellent summary of work up to 1953, see “Feldemission” by Müller, E. W., Ergeb. exakt. Naturwiss. 27, 290–360 (1953
2. Electron emission in intense electric fields
3. “Statistical Mechanics”;Mayer,1940
4. Field Emission: Large Current Densities, Space Charge, and the Vacuum Arc