1. Variation of SNOMED CT coding of clinical research concepts among coding experts;Andrews;J Am Med Inform Assoc,2007
2. Vocabulary control for information retrieval;Lancaster,1986
3. International Health Terminology Standards Development Organization. Copenhagen, Denmark. Available from: http://www.ihtsdo.org/; 2007 [accessed 23.11.07].
4. Data standards in clinical research: gaps overlaps, and challenges and future directions;Richesson;J Am Med Inform Assoc,2007
5. CliniClue Browser. Version 2006.2.0030. United Kingdom: The Clinical Information Consultancy; 2006.