sklearn.feature_extraction.text.CountVectorizer, scikit-learn developers, 2024 (scikit-learn project) - Official documentation for scikit-learn's CountVectorizer, detailing its usage for generating N-gram features.
Foundations of Statistical Natural Language Processing, Christopher D. Manning and Hinrich Schütze, 1999 (MIT Press) - A seminal textbook providing a rigorous statistical and mathematical foundation for NLP, including extensive coverage of N-gram models.