1. Indexing Languages and Thesauri: Construction and Maintenance;Soergel,1974
2. Experiments in Automatic Thesaurus Construction for Information Retrieval;Salton,1972
3. Semantic road maps for literature searchers;Doyle;Journal of the ACM,1961
4. Automatic Message Retrieval by Associative Techniques, in Joint Man-Computer Languages;Giuliano;Mitre Corporation Report SS-10,1962
5. A Framework for Representing Knowledge;Minsky,1975