Okapi at TREC-3, Stephen E. Robertson, Steve Walker, Susan Jones, Micheline Hancock-Beaulieu, Mike Gatford, 1994Proceedings of The Third Text REtrieval Conference, TREC 1994, Vol. 500-225 (National Institute of Standards and Technology (NIST)) - Describes the Okapi BM25 ranking function, a cornerstone of sparse retrieval, illustrating its effectiveness in early information retrieval evaluations.
Sentence-BERT: Sentence Embeddings using Siamese BERT-Networks, Nils Reimers, Iryna Gurevych, 2019Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP) (Association for Computational Linguistics)DOI: 10.18653/v1/D19-1410 - Presents Sentence-BERT, a modification of BERT that generates semantically meaningful sentence embeddings, a fundamental technique for dense retrieval methods.
Hybrid Search: An Overview, Adam Benayoun, 2024 (Pinecone) - A practical overview of hybrid search, explaining its components, benefits, and common implementation strategies from a vector database vendor's perspective.
LangChain Documentation: EnsembleRetriever, LangChain Developers, 2024 (LangChain) - Official documentation for LangChain's EnsembleRetriever, detailing its usage and how it combines results from multiple retrievers, including sparse and dense methods.