@Article{ThomasH09,
  author = 	 {Paul Thomas and David Hawking},
  title = 	 {Server selection methods in personal metasearch:
       a comparative empirical study},
  journal = 	 {Information Retrieval},
  year = 	 2009,
  volume = {12},
  number = {5},
 pages = {581--604},
  note = 	 {\url{http://david-hawking.net/pubs/thomas_ir09.pdf}}
}