@InJournals{chen2009 
  author = {Ya-Xi Chen, Rodrigo Santamaria, Andreas Butz, Roberto Theron},
  title  = "{TagClusters: Semantic Aggregation of Collaborative Tags beyond TagClouds}",
  booktitle = {9th International Symposium on Smart Graphics, SG 2008, Salamanca, Spain, May 28-30, 2009. Proceedings},
  year =   {2009}
  }