doi dblp The Significance of the Cranfield Tests on Index Languages Cyril W. Cleverdon Proceedings of the 14th Annual International ACM SIGIR Conference on Research and Development in Information Retrieval. Chicago, Illinois, USA, October 13-16, 1991 (Special Issue of the SIGIR Forum)
doi dblp Introduction Cyril W. Cleverdon 1968 Volume 4 Issue 2