@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://es.csiro.au/pubs/hawking_zobel_jasist.pdf}}
}