1. Livey, D. T.: Niobium: Physicochemical Properties of its Compounds and Alloys. I.A.E.A., Wien 1968.
2. Kubaschewski, O., u.T. G. Chart: J. Inst. Metals93, 329 (1965).
3. Gaube, J., et al.: Arch. Eisenhüttenw.34, 653 (1963).
4. Gilles, P. W.: Proc. I.A.E.A. Sympos. ?Thermodynamics Nuclear Materials?. Wien1, 191 (1965).
5. Komarek, K. L., u.M. Silver: ibid.Proc. I.A.E.A. Sympos. ?Thermodynamics Nuclear Materials?. Wien1962, 479.