1. I. Pratt, inGeterotsiklicheskie soedineniya [Heterocyclic Compounds], Ed. R. Elderfield, Moscow, 1960, 6, 344 (Russ. Transl.).
2. E. S. Rodionov, Ph. D. (Chem.) Thesis, State Scientific Research Institute of the Chemistry and Technology of Organoelement Compounds, Moscow, 1973, 173 (in Russian).
3. H. Niederprum and W. Sommler,Chem. Ber., 1963,96, 965.
4. W. Sommler,Chem. Ber., 1963,96, 349.
5. M. Wieber and M. Schmidt,J. Organometal. Chem., 1963,1, 22.