Vassilis Spiliopoulos Konstantinos Kotis George A. Vouros Semantic retrieval and ranking of Semantic Web documents using free-form queries. 95-108 2008 3 IJMSO 2 http://dx.doi.org/10.1504/IJMSO.2008.021888 db/journals/ijmso/ijmso3.html#SpiliopoulosKV08