1. 〈http://phasetwo.org/post/a-better-tag-cloud.html〉, 05/31/08.
2. 〈http://www.usatoday.com〉, 〈http://www.abcnews.go.com〉, 〈http://www.forbes.com〉, 〈http://www.nytimes.com〉, 〈http://www.smh.com.au〉, 〈http://www.guardian.co.uk〉, 〈http://news.bbc.co.uk〉, 〈http://www.cbsnews.com〉, 〈http://www.chron.com〉, 〈http://www.washingtonpost.com〉, 〈http://news.com.com〉, 〈http://www.boston.com〉, and 〈http://www.iht.com〉
3. G. Chintalapani, C. Plaisant, B. Shneiderman, Extending the utility of treemaps with flexible hierarchy, in: IV’04, 2004.
4. S. Deerwester, S. Dumais, G. Furnas, R. Harshman, T. Landauer, K. Lochbaum, L. Streeter. Computer information retrieval using latent semantic structure, US Patent, 1989.
5. P. Cimiano, S. Staab, J. Tane, Automatic acquisition of taxonomies from text: FCA meets NLP, in: ECML/PKDD Workshop on Adaptive Text Extraction and Mining, 2003.