1. Polmear, I. J., Nature, 186, 303 (1960).
2. Polmear, I. J., J. Inst. Metals, 89, 193 (1960–61).
3. Rosenkranz, W., Aluminium, 39, 290, 630, 741 (1963).
4. Di Russo, E., Alluminio, 33, 505 (1964); ibid., 34, 331 (1965).
5. Polmear, I. J., Trans. Met. Soc. Amer. Inst. Mech. Eng., 230, 1331 (1964).