sklearn.preprocessing.PolynomialFeatures, Scikit-learn Developers, 2023 - Official documentation for the Scikit-learn PolynomialFeatures transformer, detailing its parameters and usage.
An Introduction to Statistical Learning: With Applications in R, Gareth James, Daniela Witten, Trevor Hastie, and Robert Tibshirani, 2013 (Springer) - An accessible introduction to statistical learning methods, including chapters on linear regression, polynomial regression, and interaction terms.