1. Foy, R. & Labeyrie, A. Astr. Astrophys. 152, L29–L31 (1985).
2. Séchaud, M. et al. in Very Large Telescopes and their Instrumentation, Proceedings Vol II (ed Ulrich, M. H.) 705–714 (European Southern Observatory, Garching, 1988).
3. Beckers, J. M. in Very Large Telescopes and their Instrumentation Proceedings Vol II (ed Ulrich, M. H.) 693–703 (European Southern Observatory, Garching, 1988).
4. Gardner, C. S., Welsh, B. M. & Thompson, L. A. Proc. IEEE 78, 1721–1743 (1990).
5. Thompson, L. A. & Gardner, C. S. Nature 328, 229–231 (1987).