1. (a) , , , in: Gmelin Handbook of Inorganic Chemistry, 8th Ed., Selenium Supplement Vol. B2, Springer, Berlin 1984, S. 272;
2. (b) : Chemistry of the Elements, Pergamon Press, Oxford 1984, S. 817–819 und 901–904.
3. (a) , , , J. Chem. Soc. Chem. Commun. 1976, 689;
4. (b) , , , J. Chem. Soc. Chem. Commun. 1982, 1098.
5. , , J. Chem. Soc. Chem. Commun. 1982, 87.