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