1. E W Justi, H Hewe, W Kalberiah, N M Saridaks and M H Schaefer, Energy Conversion 10, 183 (1970)
2. N C Liderenke, C F Muchnik, D E Bogation, N M Kayer and Z A Karicher, Electronimiya 10, 808 (1974)
3. M A Gatjahr, H Buchner, K D Beccu and H Safferer, in D H Collins (ed.) Proc. 8th Int. Symp. on Power Sources, Brigton, (Sept. 1972) (Orient Press, UK, 1973) p. 72
4. P K Iyenger, Proc. Interdisciplinary Meeting on Hydrogen in Metals, Bombay, Feb. 19–20, 1980
5. P Pieter Kowasky and F G Yong Kin, J. Appl. Phys. 37, 1763 (1960)