https://www.r-bloggers.com/2020/05/simple-guide-to-ridge-regression-in-r/
https://www.datatechnotes.com/2018/10/understanding-ridge-regularization-with.html
https://bookdown.org/tpinto_home/Regularisation/ridge-regression.html
https://rpubs.com/skydome20/R-Note18-Subsets_Shrinkage_Methods
https://jamleecute.web.app/regularized-regression-ridge-lasso-elastic/
https://www.ncss.com/wp-content/themes/ncss/pdf/Procedures/NCSS/Ridge_Regression.pdf
https://glmnet.stanford.edu/articles/glmnet.html