sklearn.feature_selection.VarianceThreshold, scikit-learn developers, 2023 - Official documentation for the VarianceThreshold transformer, providing usage examples and parameter details.
Applied Predictive Modeling, Max Kuhn and Kjell Johnson, 2013 (Springer)DOI: 10.1007/978-1-4614-6849-3 - A practical guide that discusses data preprocessing techniques, including identifying and handling zero- and near-zero variance features, and general feature selection strategies.
The Elements of Statistical Learning: Data Mining, Inference, and Prediction, Trevor Hastie, Robert Tibshirani, Jerome Friedman, 2009 (Springer) - A comprehensive textbook covering statistical learning theory, with foundational chapters on feature selection and dimensionality reduction relevant to understanding filter methods.