Event Time and Watermarks, The Apache Flink Community, 2023 (The Apache Flink Community) - Official documentation explaining Flink's event time processing model, including watermarks and their role in stream completeness.
Windows, The Apache Flink Community, 2023 - Detailed official documentation on Flink's windowing mechanisms, specifically covering allowed lateness and side outputs for handling late data.
Streaming Systems: The What, Where, When, and How of Large-Scale Data Processing, Tyler Akidau, Slava Chernyak, Reuven Lax, 2018 (O'Reilly Media) - A foundational text on stream processing, providing theoretical and practical understanding of event time, watermarks, and consistency models essential for handling late data in distributed systems.