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Marshall, L.G. 1981: The Great American Interchange - an invasion induced crisis for South American mammals. In Nitecki, M.H. , editor, Biotic crises in ecological and evolutionary time , New York: Academic Press , 133-229.

May, R.M. 1973: Stability and complexity in model ecosystems. Princeton: Princeton University Press.

Pimm, S.L. 1982: Food webs. London: Chapman and Hall.