1. Low Temperature Nuclear Orientation, eds N.J. Stone and H. Postma (North-Holland, Amsterdam, 1986).
2. A. Abragam and B. Bleaney,Electron Paramagnetic Resonance of Transition Ions (Oxford Univ. Press, Oxford, 1970).
3. W.D. Brewer,ibid, chapter 9, ref. [1]..
4. D.I. Bradley, J.P. White, C.J. Ashworth, J. Rikovska and N.J. Stone, Hyp. Int. 35 (1987) 1033.
5. On-line facilities exist at KOOL, Louvain la Neuve, Belgium; DOLIS-COLD, SERC Daresbury, UK; NICOLE, ISOLDE-3, CERN, Geneva, Switzerland; and at UNISOR, Oak Ridge, USA.