1. Multidimensional Scaling;Cox,2001
2. Indexing by latent semantic analysis;Deerwester;J. Soc. Inform. Sci.,1990
3. Improving the retrieval of information from external sources;Dumais;Behavior Res. Methods Instrum. Comput.,1991
4. The Elements of Statistical Learning: Data-Mining, Inference and Prediction;Hastie,2001
5. Principal Component Analysis;Jolliffe,2002