ChEMBL is medicinal chemistry database by the team of dr. J. Overington at the EBI: http://www.ebi.ac.uk/chembl/ It is detailed in this paper (doi:10.1093/nar/gkr777): http://nar.oxfordjournals.org/content/early/2011/09/22/nar.gkr777.short This project develops, releases, and hosts a RDF version of ChEMBL, independent from the ChEMBL team who make their own RDF version. The main SPARQL end point is available from Uppsala University at: http://rdf.farmbio.uu.se/chembl/sparql