1. J.M. Fournier and R. Tro c, in:Handbook on the Physics and Chemistry of the Actinides, eds. A.J. Freeman and G.H. Lander, Vol. 2 (North-Holland, Amsterdam, 1985) p. 29.
2. F. Hulliger, in:Handbook on the Physics and Chemistry of Rare-Earth, eds. K.A. Gschneider Jr. and L. Eyring, (North-Holland, Amsterdam, 1979) Ch. 33.
3. B.R. Cooper, R. Siemann, D. Yang, P. Thayamballi and A. Banerjea, see ref. [1] p. 435.
4. A. Schenck,Muon Spin Rotation Spectroscopy (Adam Hilger, Bristol, 1985).
5. O. Hartmann, invited talk at this conference.