Product Quantization for Nearest Neighbor Search, Jégou, Hervé, Douze, Matthijs, and Schmid, Cordelia, 2011IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol. 33 (IEEE)DOI: 10.1109/TPAMI.2010.207 - The original paper detailing Product Quantization (PQ), a fundamental technique for compressing high-dimensional vectors to reduce memory footprint.