@ARTICLE{
       Author = {Papadopoulos, F. and Kitsak, M. and Serrano, M. and Boguñá, M. and Krioukov, D.}, 
       Title = {{Popularity versus Similarity in Growing Networks}},
       Journal = {Nature}, 
       Volume = {489},
       Pages = {537-540},
       Month = {Sep},
       Year = {2012},
       Keywords = {topology   network geometry   routing}
}