John S. Garofolo Cedric G. P. Auzanne Ellen M. Voorhees The TREC Spoken Document Retrieval Track: A Success Story. 1999 TREC http://trec.nist.gov/pubs/trec8/papers/trec8-sdr-overview.pdf db/conf/trec/trec1999.html#GarofoloAV99