I really like the way Harrell uses PCA to build regression analysis in Regression Modeling Strategies https://link.springer.com/book/10.1007/978-3-319-19425-7

I really like the way Harrell uses PCA to build regression analysis in Regression Modeling Strategies https://link.springer.com/book/10.1007/978-3-319-19425-7 https://link.springer.com/book/10.1007/978-3-319-19425-7