1. J.T. Walton NIM A 226, 1(1984), E.H.M. Heijne, ibid 63, H.Boettcheiybid, 72, J.Kemmer, ibid, 89, E.Gatti,ibid,163, G.Zimmer, ibid, 175.
2. J. Kemmer NIM A 253, 365(1987), E.H.M. Heijne, ibid, 325, W.R.Th. Ten Kate, ibid, 333. A.H.Walente, ibid, 558.
3. M. Cacciai NIM A 260,124(1987).
4. S. Holland NIM A 275, 537(1989), IEEE Trans, on NS, 36/1, 283(1989).
5. J. Kemmer NIM A 288, 262(1990), E.Fretwurst, ibid, 1, AXongoni, ibid, 35, T. Maish, ibid, 89.