Aviezri S. Fraenkel. Document Classification, Indexing and Abstracting May be Inherently Difficult Problems. In Carolyn J. Crouch, editor, Theoretical Issues in Information Retrieval, Proceedings of the Fourth International Conference on Information Storage and Retrieval, Oakland, California, USA, May 31 - June 2, 1981. pages 77-82, ACM, 1981. [doi]
Abstract is missing.