1. Gracenote http://www.gracenote.com/
2. Midomi http://www.midomi.co.jp
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4. Audio fingerprinting: nearest neighbor search in high dimensional binary spaces;Miller;J VLSI Sign Process,2005
5. Wang ALC An industrial-strength audio search algorithm Proceedings of the 4th International Conference on Music Information Retrieval ISMIR 2003 7 13 2003