Daniels, P.J., Brooks, H.M. & Belkin, N.J. (1997) Using problem structures for driving humancomputer dialogues. In: Readings in Information Retrieval, edited by K. Sparck Jones and P. Willett. San Francisco, Morgan Kaufmann, 1997: 135-142. A reprint of: Daniels, P.J., Brooks,
Readings in Information Retrieval