1. Yannas, I. V. and Tobolsky, A. V., Eur. Polym. J., 1968, 4, 257.
2. Yannas, I. V., Diss. Abstr., 1966, B-37, 1873.
3. Burdygina, G. I., Fridman, I. M., Koslov, P. V. and Kargin, V. A., Vysokomol, Soedin, 1969, Ser. A11, 118.
4. Burdygina, G. I., Undzenas, A., Fridman, I. M., Koslov, P. V. and Kargin, V. A., Dokl. Adad Nauk, SSSR, 1968, 178, 1360.
5. Monier, J. B., U.S. Pat. 2363892 and 2732303, 1944.