1. Halpern, D.F. & Coren, S. Nature 333, 213 (1988).
2. Wood, E.K. Nature 335, 212 (1988).
3. Neft, D.S. & Cohen, R.M. The Sports Encyclopedia: Baseball 8th edn (St Martin's Press, New York, 1988).
4. Snedecor, G.W. & Cochran, W.G. Statistical Methods (Iowa State University Press, Ames, 1967).