1. K. M. Entwistle,J. Mater. Sci. 26 (1991) 1078.
2. Idem. ibid. 28 (1993) 2007.
3. C. J. Smithells (ed.) ?Metals reference book?, 4th Edn (Butterworths, London, 1967) p. 708.
4. S. P. Timoshenko andS. Woinowsky-Krieger, ?Theory of plates and shells?, 2nd Edn (McGraw Hill, Singapore, 1959) p. 48.