1. M. I. Bessonov, M. M. Koton, V. V. Kudryavtsev, and L. A. Laius, Polyimides: A Class of Thermostable Polymers (Nauka, Leningrad, 1983) [in Russian].
2. H. Ohya, V. V. Kudryavtsev, and S. I. Semenova, in Polyimide Membranes: Applications, Fabrications, and Properties (Gordon and Breach, Tokyo, 1996), p. 314.
3. T. Nakagawa, in Polymeric Gas Separation Membranes, Ed. by D. R. Paul and Yu. P. Yampolskii (CRC, Boca Raton, 1994), p. 314.
4. Y. Hirayama, T. Yoshinaga, S. Nakanishi, and Y. Kusuki, in Polymer Membranes in Gas and Vapor Separation, Ed. by B. D. Freeman and I. Pinnau (Am. Chem. Soc., Washington, 1999), p. 194.
5. I. E. Kardash and A. N. Pravednikov, Vysokomol. Soedin., Ser. B 9, 873 (1967).