1. G. Sandrock: “Applications of Hydrides”, this volume
2. T. Graham: Phil. Trans. Royal Soc., 156 (1866) 415
3. T. Graham: Proc. Royal Soc., 16 (1868) 422
4. D.P. Smith: Hydrogen in Metals, U. of Chicago Press, Chicago, 1948
5. L Schlapbach: “Introduction”, in Ref.27, Vol.I, p.1