1. Collett, T. S. & Harknes, L. I. K. in Analysis of Visual Behaviour (eds Ingle, D. J., Goodale, M. A. & Mansfield, J. W.) 111–175 (MIT Press, 1982).
2. Lissmann, H. W. & Machin, K. E. The mechanism of object location in Gymnarchus niloticus and similar fish. J. Exp. Biol. 35, 451–486 (1958).
3. von der Emde, G. in The Physiology of Fishes (ed. Evans, D. H.) 313–343 (CRC, Boca Raton, 1998).
4. Bastian, J. in Comparative Perception (eds Stebbins, W. C. & Berkeley, M. H.) 35–89 (Wiley, New York, 1989).
5. Schwarz, S. Diplomarbeit, Institut für Zoologie, Universität Bonn (1997).