State & Fault Tolerance, The Apache Flink Community, 2024 - Provides foundational information on Flink's state mechanisms, including keyed state, operator state, checkpointing, and guarantees.
Apache Flink: Stream Processing for Real-time Applications, Fabian Hueske and Vasia Kalavri, 2019 (O'Reilly Media) - A comprehensive guide by Flink committers, covering Flink's architecture, API, state management patterns (including broadcast state), and deployment.