1. W. C. Elmore, E. M. Little, and W. E. Quinn, inProceedings of the Second United Nations International Conference on the Peaceful Uses of Atomic Energy(United Nations, Geneva, 1958), Vol. 32, p. 337.
2. A. C. Kolb, inProceedings of the Second United Nations International Conference on the Peaceful Uses of Atomic Energy(United Nations, Geneva, 1958), Vol. 31, p. 328.
3. H. A. B. Bodin, T. S. Green, G. B. F. Niblett, and N. J. Peacock, inProceedings of the Fourth International Conference on Ionization Phenomena in Gases, Uppsala, 1959(North-Holland Publishing Company, Amsterdam, 1960), Vol. II, p. 1061.
4. H. Fay, E. Hintz and H. L. Jordan,Proceedings of the Fourth International Conference on Ionization Phenomena in Gases, Uppsala, 1959(North-Holland Publishing Company, Amsterdam, 1960), Vol. II, p. 1046.