Belsley, D.A., Kuh, E. and Welsch, R., “Regression Diagnostics,” 1980, John Wiley and Sons, New York.

Berger, J.O. and Bock, M.E., “Combining independent normal mean estimation problems with unknown variances,” Ann. Statist. 4, 1976, pp. 642–648.

Breiman, L., Friedman, J., Olshen, R. and Stone, J., “Classification and Regression Trees,” 1984, Wadsworth, California.

Breiman, L. and Friedman, J.H., “Estimating Optimal Transformations in Multiple Regression and Correlation (with discussion),” J. Amer. Statist. Assoc., 80, 1985, pp. 580–619.

Breiman, L. and Spector, P., “Submodel Selection and Evaluation-*X* Random Case,” International Statistical Review, 3, 1992, pp. 291–319.

Efron, B. and Morris, C., “Combining possibly related estimation problems (with discussion),” J. Roy. Statist. Soc. Ser. B, 35, 1973, pp. 379–421.

Green, E.J. and Strawderman, W.E., “A James-Stein type estimator for combining unbiased and possibly biased estimators,” J. Amer. Statist. Assoc., 86, 1991, pp. 1001–1006.

Hoerl, A.E. and Kennard, R.W., “Ridge regression: Biased estimation for nonorthogonal problems,” Technometrics, 12, 1970, pp. 55–67.

Lawson, J. and Hanson, R., “Solving Least Squares Problems,” 1974, Prentice-Hall, New Jersey.

Luenberger, D., “Linear and Nonlinear Programming,” 1984, Addison-Wesley Publishing Co.

Le Blanc, M. and Tibshirani, R., “Combining Estimates in Regression and Classification,” Technical Report 9318, 1973, Dept. of Statistics, University of Toronto.

Perrone, M.P., “General Averaging Results for Convex Optimization,” Proceedings of the 1993 Connectionist Models Summer School, Erlbaum Associates, 1994, pp. 364–371.

Rao, J.N.K. and Subrathmaniam, K., “Combining independent estimators and estimation in linear regression with unequal variances,” Biometrics, 27, 1971, pp. 971–990.

Rubin, D.B. and Weisberg, S., “The variance of a linear combination of independent estimators using estimated weights,” Biometrika, 62, 1975, pp. 708–709.

Wolpert, D., “Stacked Generalization,” Neural Networks, Vol. 5, 1992, pp. 241–259.