1. J. E. Mark, H. R. Allcock, and R. West, Inorganic Polymers, 2nd ed. (Oxford, New York, 2005) Chap. 3
2. Some early references: (a) J. Liebig, Justus Liebigs Ann Chem. 11, 139 (1834). (b) C. Gerhardt, Ann. Chim. Phys. 18, 188 (1846). (c) J. H. Gladstone and J. D. Holmes, J. Chem. Soc. 17, 225 (1864). (d) J. H. Gladstone, J. Chem. Soc. 2, 121 (1850). (e) H. N. Stokes, Amer. Chem. J. 18, 629 (1896).
3. (a) H. R. Allcock, Chemistry and Applications of Polyphosphazenes (Wiley-Interscience, New York, 2003) Chap. 4, 5.
4. (b) H. R. Allcock, Chem. Rev. 72, 315 (1972).
5. (a) J. Emsley and P. B. Udy, J. Chem. Soc. A 3025 (1970).