1. Cluster Analysis: Bibliography;Crouch;ACM SIGIR Forum,1971
2. The Use of Automatically-Obtained Keyword Classifications for Information Retrieval;Sparck Jones;Information Storage and Retrieval,1970
3. Automatic Term Classifications and Retrieval;Sparck;Information Storage and Retrieval,1968
4. Deriving Term Relations for a Corpus by Graph Theoretical Clusters;Augusto;Journal of the American Society for Information Science,1970