1. Matrix algebra;Abadir,2005
2. An introduction to multivariate statistical analysis;Anderson,1958
3. The combination of forecasts;Bates;Operational Research Quarterly,1969
4. Elliott, G. (2011). Averaging and the optimal combination of forecasts. UCSD working paper, http://econweb.ucsd.edu/~grelliott/AveragingOptimal.pdf.
5. Combining forecasts: An application to elections;Graefe;International Journal of Forecasting,2014