1. Siri, W. E.: Isotopic Tracers and Nuclear Radiations. New York: McGraw Hill Book Company 1949.
2. Borkowski, C. J.: Report of US Atomic Energy Commission MDDC-1099
3. Corson, D. R., u. R. R. WILSON: R. S. I. 19, 207 (1948).
4. Brownell, G. L., u. H. S. Lockhart: Nucleonics 10 (2), 26 (1952).
5. Lauritsen, C. C., U. T. Lauritsen: RSI 8, 438 (1937).