User Guide: Supervised learning, Scikit-learn Developers, 2023 - Official documentation explaining the common API for supervised estimators, including the fit() method, its inputs, and how it trains a model.
The Elements of Statistical Learning: Data Mining, Inference, and Prediction, Trevor Hastie, Robert Tibshirani, and Jerome Friedman, 2009 (Springer) - A classic reference that provides a rigorous statistical and mathematical foundation for machine learning algorithms, explaining how models learn and fit data.
Introduction to Machine Learning, Ethem Alpaydın, 2020 (The MIT Press) - Offers a comprehensive overview of fundamental machine learning principles, including the supervised learning paradigm and the mechanics of model training.