Integrating BM25 & BM25F into Lucene Joaquín Pérez-Iglesias Introduction This document describes the BM25 and BM25F implementation using the Lucene Java Framework. The implementation described here can be downloaded from http://nlp.uned.es/~jperezi/Lucene-BM25/jar/models.jar. Both models have stood out at TREC by their performance and are considered as state-of-the-art in the IR community. BM25 i