1. V E Bubelev, D H Madison and M A Pinkerton J. Phys. B29 1751 (1996)
2. V Zeman, R P McEachran and A D Stauffer Eur. Phys. J. D1 117 (1998)
3. J Ward, M Horbatsch, R P McEachran and A D Staufer J. Phys. B22 1845 (1989)
4. R N Hewitt, C J Noble and B H Bransden J. Phys. B25 2683 (1992)
5. M T McAlinden, A A Kernoghan and H R J Walters Hyperfine Interactions 89 161 (1994); J. Phys. B29 555 (1996)