\begin{thebibliography}{10} \bibitem{BecRCW88} Richard~A. Becker, John~M. Chambers, and Allan~R. Wilks. \newblock {\em The S Language; A Programming Environment for Data Analysis and Graphics}. \newblock Wadsworth \& Brooks/Cole, Pacific Grove, 1988. \bibitem{ChaJ98} John~M. Chambers. \newblock {\em Programming with Data; A Guide to the S Language}. \newblock Springer-Verlag, New York, 1998. \bibitem{ChaJH92} John~M. Chambers and Trevor~J. Hastie. \newblock {\em Statistical Models in S}. \newblock Wadsworth \& Brooks/Cole, 1992. \bibitem{Cook:Weisberg:1999} R.~Dennis Cook and Sanford Weisberg. \newblock {\em Applied Regression Including Computing and Graphics}. \newblock John Wiley \& Sons, August 1999. \bibitem{ihak:gent:1996} Ross Ihaka and Robert Gentleman. \newblock R: {A} language for data analysis and graphics. \newblock {\em Journal of Computational and Graphical Statistics}, 5:299--314, 1996. \bibitem{Splus} MathSoft. \newblock S-plus statistical software: Release 5.1, 2000. \newblock Seattle, WA: MathSoft. \bibitem{ESS} A.J. Rossini, Martin M{\"a}chler, Kurt Hornik, Richard~M. Heiberger, and Rodney Sparapani. \newblock E{S}{S} (emacs speaks statistics), 2001. \newblock \texttt{ess.stat.wisc.edu/pub/ESS/}. \bibitem{SAS:8.0} {SAS Institute}. \newblock S{A}{S} statistical software: Release 8.0, 2000. \newblock Cary, NC: SAS Institute. \bibitem{RMS:2000} Richard~M. Stallman. \newblock {\em GNU Emacs Manual, for Version 20.7}. \newblock Free Software Foundation, 13th edition, 2000. \bibitem{Stata:6.0} StataCorp. \newblock Stata statistical software: Release 6.0, 1999. \newblock College Station, TX: Stata Corporation. \bibitem{DTLang:2000} Duncan {Temple Lang}. \newblock The omegahat environment: New possibilities for statistical computing. \newblock {\em Journal of Computational and Graphical Statistics}, 9(3), September 2000. \bibitem{Tier90} Luke Tierney. \newblock {\em Lisp-Stat: An Object-Oriented Environment for Statistical Computing and Dynamic Graphics}. \newblock John Wiley \& Sons, New York, 1990. \bibitem{vell:prat:1989} Paul~F. Velleman and Paul Pratt. \newblock A graphical interface for data analysis. \newblock {\em Journal of Statistical Computation and Simulation}, 32:223--228, 1989. \bibitem{youn:fald:mcfa:1992} Forrest~W. Young, Richard~A. Faldowski, and Mary~M. McFarlane. \newblock Vista: {A} visual statistics research and development testbed. \newblock In {\em Computing Science and Statistics. Proceedings of the 24rd Symposium on the Interface}, pages 224--233. Interface Foundation of North America (Fairfax Station, VA), 1992. \bibitem{youn:lubi:1995} Forrest~W. Young and David~J. Lubinsky. \newblock Guiding data analysts with visual statistical strategies (disc: P251--260). \newblock {\em Journal of Computational and Graphical Statistics}, 4:229--250, 1995. \end{thebibliography}