SYNTHESIS OF OLIGOMERIC EPOXYCYCLOTRIPHOSPHAZENES AND THEIR PROPERTIES AS REACTIVE FLAME-RETARDANTS FOR EPOXY RESINS Article Terekhov I.V., Filatov S.N., Chistyakov E.M., Borisov R.S., Kireev V.V. Phosphorus, Sulfur and Silicon and the Related Elements. Taylor and Francis Ltd.. Vol. 192. 2017. P. 544-554