The original UML mapping sets were extracted from the MRCONSO.RRF file of the UMLS  2009AA distribution files (see  for details).
In  it was noticed that the integration of the (formally represented) UMLS mappings together with the input ontologies was leading to numerous logical errors. To address this problem, in  and  two refinements of the UMLS mappings were presented that do not lead to such inconsistencies.
In the OAEI track we will consider the refined subset proposed in , since it was generated using "less aggressive" ontology repair techniques.
Please consider citing ,  and  when you use the UMLS-based reference alignments.