1. Proc. III Int. Conf. on Elect. Tech.;Voss,1981
2. N.R.S. Tait, these proceedings (6th Tandem Conf.), p. 54.
3. Proc. III Int. Conf. on Electr. Tech.;Joy,1981
4. Ion exchange currents in vacuum accelerator tubes
5. D.A. Eastham, these proceedings (6th Tandem Conf.), p. 101.