1. Parker, G. A., Baker, R. R. & Smith, V. G. F. J. theor. Biol. 36, 529–553 (1972).
2. Pitnick, S., Spicer, G. S. & Markow, T. A. Nature 375, 109 (1995).
3. Brady, R. et al. in Proc. biomed. Visualization '95 (eds Loew, M. & Gershon, N.) 1825 (IEEE Computer Society, Los Alamitos, CA, 1995).
4. Cruz-Neira, C., Sandin, D. J., DeFanti, T. A., Kenyon, R. & Hart, J. C. Commun. Ass. Comput. Mach. 35, 64–72 (1992).
5. Bressac, C., Fleury, A. & Lachaise, D. Proc. natn. Acad. Sci. U.S.A. 91, 10399–10402 (1994).