1. Boorman, S.A. & P.R. Levitt. 1980. The genetics of altruism. Academic Press, New York. 459 pp.
2. Harvey, P.H. & P.J. Greenwood. 1978. Anti-predator defence strategies: some evolutionary problems. pp. 129?151.In J.R. Krebs & N.B. Davies (ed.) Behavioural Ecology, Sinauer Assoc., Sunderland.
3. Kubista, I. 1980. Minnesota bait farmer contributes to multimillion dollar state crop. Aquaculture Magazine 616: 28?30.
4. Pfeiffer, W. 1974. Pheromones in fish and amphibia. pp. 269?296.In: M.C. Birch (ed.) Pheromones, Frontiers of Biology, Vol. 32, North-Holland Publ., Amsterdam.
5. Pfeiffer, W. 1982. Chemical signals in communication. pp. 306?326.In: T.J. Hara (ed.) Chemoreception in Fishes, Elsevier, Amsterdam.