1 M.W. Hamilton, K.. Arnett, S.J. Smith, D.S. Elliott, M.. Dziemballa, and P.. Zoller, Physical Review A 36, (1987).
1 K.. Arnett, S.J. Smith, R.. Ryan, T.. Bergeman, H.. Metcalf, M.W. Hamilton, and J.R. Brandenberger, Physical Review A 41, (1990).