Vladimir Dobrynin Son Kim Pham David Patterson Niall Rooney Mykola Galushka SOPHIA in Enterprise Track. 2006 TREC http://trec.nist.gov/pubs/trec15/papers/uulster.ent.final.pdf conf/trec/2006 db/conf/trec/trec2006.html#DobryninPPRG06