1. R. W. Armstrong andW. H. Robinson,N.Z.J. Sci. 17 (1974) 429.
2. H. R. Hertz, ?Miscellaneous Papers? (Macmillan, London, 1896) Chs. 5, 6.
3. S. P. Timoshenko andJ. N. Goodier, ?Theory of Elasticity? (McGraw-Hill, New York, 1970).
4. I. D. Cave,Wood Sci. and Tech. 3 (1969) 40.
5. Idem, ibid 6 (1972) 157.