1. F. A. Cotton and R. Walman, Multiple Metal-Metal Bonds [Russian translation], Mir, Moscow (1985), p. 535.
2. A. H. Cowley and N. C. Norman, Progress in Inorganic Chemistry, Wiley, New York (1986), p. 320.
3. J. R. Van Wazer, Phosphorus and Its Compounds, Vol. 1, Chemistry, Wiley Interscience, New York (1958).
4. R. F. Hudson, Structure and Mechanism in Organophosphorus Chemistry, Academic Press, New York (1965).
5. A. J. Kirby and S. G. Warren, The Organic Chemistry of Phosphorus, Elsevier, New York (1967).