1. R. P. Kambour, J. Polymer Sci. D 7(1973) 1.
2. P. B. Bowden, in ?The Physics of Glassy Polymers? edited by R. N. Haward (Applied Science Publishers, London, 1973).
3. P. J. F. Wright, Mag. Concrete Res. 7 (1955) 87.
4. D. Kells and N. J. Mills, Phil Mag. A44 (1981) 1149.
5. R. J. Izbicki, Bull. Acad. Pol. Sci., Ser. des Sci. Tech. 20 (1972) 255.