1. The Theory of Collectors in Gaseous Discharges
2. E. H. Walker, inInteraction of Space Vehicles with an Ionized Atmosphere, edited by S. F. Singer (Pergamon Press Inc., New York, 1965).
3. E. J. Öpik, inInteraction of Space Vehicles with an Ionized Atmosphere, edited by S. F. Singer (Pergamon Press Inc., New York, 1964).