1. International Atomic Energy Agency (IAEA-Tech. Rept. Ser. No. 39 [1965] 1/105, 3/4; IAEA Bull. 7 No. 2 [1965] 48).
2. R. Hawes (private communication from [1]).
3. F. Gronvold (J. Inorg. Nucl. Chem. 1 [1955] 357/70).
4. Centre d’Etude pour les Applications de l’Energie NuclEaire (EURAEC-266 [1961] 1/14; R-2082 [1961] 1/14; N.S.A. 16 [1962] No. 30377).
5. F. Foot, E.R. Jette (Phys. Rev. [2] 58 [1940] 81/6).