Sparse matrices, SciPy Developers, 2023 - Documentation detailing the various formats and functionalities of sparse matrices within SciPy, essential for memory-efficient handling of high-dimensional, sparse datasets.
NumPy User Guide, NumPy Developers, 2023 - Provides foundational information on NumPy's array object, array creation, and data types, which underpins the data structures used in Scikit-learn.