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2. J.R. Srour, S.C. Chen, S. Othmer and R.A. Hartman, IEEE Trans. Nucl. Sci. NS-26 (1979) 4784.
3. A.J. Stevens, Brookhaven National Laboratory, performed these calculations.
4. H.W. Kraner, R.H. Pehl and E.E. Haller, IEEE Trans. Nucl. Sci. NS-22 1, (1975) 149.
5. E.E. Haller, W.L. Hanesn and F.S. Goulding, IEEE Trans. Nucl. Sci. NS-19, 3, (1972) 271.