1. RQL: a declarative query language for RDF;Karvounarakis,2002
2. Object Management Group (OMG), Unified language specification, http://www.omg.org.
3. Clinical Trials. A Practical Approach;Pocock,1998
4. Statistical data and metadata quality assessment;Vardaki,2007
5. EBM metadata based on Dublin core better presenting validity of clinical trials;Xu;J. Med. Syst.,2007