1. A. K. Efa, L. V. Tsyro, L. N. Andreeva, et al., Khim. Tekhnol. Topl. Masel, No. 4, 5 (2002).
2. G. I. Gorshenina and N. V. Mikhailov, Polymer-Asphalt Insulating Materials [in Russian], Gostoptekhizdat, Moscow (1967).
3. H. R. Allcock, Phosphazene Compounds [Russian translation], Mir, Moscow (1976).
4. V. A. Davydova and M. G. Voronkov, Polyphosphazenes [in Russian], Izd. AN SSSR, Moscow (1962).