Merge, join, concatenate and compare, pandas development team, 2024 - The primary and most up-to-date documentation for combining DataFrames, covering pd.merge and DataFrame.join methods with comprehensive examples.
Python for Data Analysis, Wes McKinney, 2022 (O'Reilly Media) - A fundamental text by the creator of Pandas, offering clear explanations and practical applications of data combining operations, including index-based merging.
Effective Pandas: Patterns for Better Use of DataFrames, Matt Harrison, 2021 (Pragmatic Bookshelf) - Provides practical patterns and efficient techniques for using Pandas, with sections dedicated to combining DataFrames effectively using merge and join.