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2. Erickson, Roberts, and Dabbs, Rev. Sci. Instr. (in press).
3. National Nuclear Energy Series VIII-5, “The Chemistry of Uranium,” pp. 533–536.
4. R. P. Hudson and C. K. McLane, International Conference on Low Temperature Physics, Houston (1953).
5. M. J. Steenland, International Conference on Low Temperature Physics, Houston (1953).