1. Thomas, R.H., Schaffner, W., Wilson, A.C. & Paabo, S. Nature 340, 465–467 (1989).
2. Farris, J.S. Syst. Zool. 28, 483–519 (1979).
3. Faith, D.P. Cladistics 5, 235–258 (1989).
4. Clemens, W.A., Richardson, B.J. & Baverstock, P.R. in Fauna of Australia Mammalia (eds Walton, D.W. & Richardson, B.J.) 527–548 (AGPS, Canberra, 1989).
5. Faith, D. P. & Cranston, P. S. Cladistics (in the press).