1. The 20 newsgroups data set, http://www.ai.mit.edu/~jrennie/20Newsgroups/
2. Internet movie database, http://www.imdb.com
3. Amini, M.-R., Gallinari, P.: The use of unlabeled data to improve supervised learning for text summarization. In: SIGIR 2002, pp. 105–112. ACM Press, New York (2002)
4. Baeza-Yates, R., Ribeiro-Neto, B.: Modern Information Retrieval. Addison-Wesley, Reading (1999)
5. Bennett, K.P., Demiriz, A.: Semi-supervised support vector machines. In: NIPS 1999, pp. 368–374. MIT Press, Cambridge (1999)