Hurtado, C.A. and Levene, Mark (2006) Discovering context-topic rules in search engine logs. In: Crestani, F. and Ferragina, P. and Sanderson, M. (eds.) International Symposium on String Processing and Information Retrieval. Lecture Notes in Computer Science 4209. Springer, pp. 346-353. ISBN 978-3-540-45774-9.