@article{HawkingZ07,
 author = {David Hawking and Justin Zobel},
 title = {Does Topic Metadata Help with Web Search?},
 journal = {JASIST},
 year = {2007},
 volume = {58},
 number = {5},
 pages = {613-628},
 note = {Preprint at \url{http://david-hawking.net/pubs/hawking_zobel_jasist.pdf}}
}