Harsha Gurulingappa Bernd Müller Roman Klinger Heinz-Theodor Mevissen Martin Hofmann-Apitius Juliane Fluck Christoph M. Friedrich Patent Retrieval in Chemistry Based on Semantically Tagged Named Entities. 2009 TREC http://trec.nist.gov/pubs/trec18/papers/scai.CHEM.pdf conf/trec/2009 db/conf/trec/trec2009.html#GurulingappaMKMHFF09