Apache Kafka Documentation, The Apache Software Foundation, 2024 (The Apache Software Foundation) - The official documentation provides authoritative details on Kafka's replication protocol, ISRs, LEO, HW, and configurations like acks and min.insync.replicas.
Kafka: The Definitive Guide, 2nd Edition, Gwen Shapira, Todd Palino, Rajini Sivaram, Krit Petty, 2021 (O'Reilly Media) - A comprehensive book covering Kafka's architecture, including detailed explanations of replication, ISRs, and consistency guarantees.