1. paper 8;L. S. Norwood,1979
2. paper 12;H. A. Barker,1979
3. R. C. Roberts, Reinforced Plastics Congress (BPF) Brighton 1978, paper 19.
4. H. H. Collins,Plast. Rubber Mater. Appl. 3 (1978) 6.
5. P. J. Hogg, D. Hull andM. J. Legg, in ?Composite Structures?, edited by I. H. Marshall (Applied Science, London, 1980) p. 106.