1. Beyer, M. (1952) ‘La Physique des Cometes,’ Mem. Soc. Roy. de Liege 13, 236.
2. Blackwell, H.R. (1946) ‘Contrast thresholds of the human eye’, J. Opt. Soc. Am. 36, 624.
3. Bobrovnikoff, N.T. (1941) ‘Investigations of the brightness of comets, Part 1 and 2’, Contributions from the Perkins Observatory, Nos. 15 and 16.
4. Bouma, R.J. (1987) ‘The lightcurve of P/Halley: An analysis of amateur observations’, Proc. International Halley Seminar, Alden Biesen, Belgium.
5. Divine, N., Fechtig, H., Gombosi, T.I., Hanner, M.S., Keller, H.U., Larson, S.M., Mendis, D.A., Newburn, R.L., Reinhard, R., Sekanina, Z., and Yeomans, D.K. (1986) ‘The Comet Halley dust and gas environment’, Space Science Reviews 43, 1–104.