Categorical data, pandas development team, 2024 - Official documentation for pandas' categorical data type, explaining its usage, advantages, and memory optimization.
Python for Data Analysis, Wes McKinney, 2022 (O'Reilly Media) - A foundational book for using pandas, with dedicated sections on data types, string operations, and categorical data.
Data Mining: Concepts and Techniques, Jiawei Han, Jian Pei, and Hanghang Tong, 2022 (Morgan Kaufmann) - A comprehensive textbook on data mining, featuring chapters on data preprocessing that discuss data types, their characteristics, and their impact on data quality and analysis.