Greedy Function Approximation: A Gradient Boosting Machine, Jerome H. Friedman, 2001The Annals of Statistics, Vol. 29 (Institute of Mathematical Statistics)DOI: 10.1214/aos/1013203445 - This foundational paper introduces the gradient boosting machine algorithm, detailing the roles of the number of boosting iterations (estimators) and the shrinkage parameter (learning rate) in model construction and regularization.
XGBoost Python API Reference, XGBoost Contributors, 2023 - The official API reference for XGBoost's Python package, detailing the XGBClassifier class parameters like n_estimators and learning_rate (eta), and the fit method's early_stopping_rounds argument for efficient tuning.