1. See, for instance, J.M. Lawrence, P.S. Riseborough and R.D. Parks, Rep. Prog. Phys. 44 (1981) 1.
2. S.K. Malik, G.K. Shenoy, P.L. Paulose, R. Nagarajan, A.E. Dwight, P.P. Vaishnava and C.W. Kimball, to appear in Hyperfine Interactions.
3. A.E. Dwight, to be published.
4. S.K. Malik, B.D. Dunlap and A.E. Dwight, Presented at the 17th Rare earth Research Conference, Hamilton, Ontario, Canada, June 1986.
5. S.K. Malik, D.T. Adroja, B.D. Padalia and R. Vijayaraghavan, see proceedings of this conference.