1. M. F. A'Hearn, S. Hoban, P. V. Birch, C. Bowers, R. Martin andD. A. Klinglesmith:Nature (London,324, 649 (1986).
2. M. F. A'Hearn, S. Hoban, P. V. Birch, C. Bowers, R. Martin andD. A. Klinglesmith:Gaseous jets in comet Halley, inXX ESLAB Symposium, ESA SP.250, Vol. I (1986), p. 483.
3. S. Larson, Z. Sekanina, D. Levy, S. Tapia andM. Senay:Comet Halley near-nucleus phenomena in 1986, inXX ESLAB Symposium, ESA SP-250, Vol. II (1986), p. 145.
4. C. B. Cosmovici, P. Mack, G. Selrwarz, A. Craubner andW. I. Ip: inSymposium on Diversity and Similarity of Comets, ESA SP-278 (1987), p. 195.
5. G. Agnelli, E. Amata, G. Bellucci, V. Formisano andG. Natali:Evaluation of a CCD Thomson 7882 for Astronomical Use, ESO/OHP Workshop (1986), p. 17.