@ARTICLE{
       Author = {Boguñá, M. and Krioukov, D. and claffy, k.}, 
       Title = {{Navigability of Complex Networks}},
       Journal = {Nature Physics}, 
       Volume = {5},
       Number = {1},
       Pages = {74-80},
       Month = {Jan},
       Year = {2009},
       Keywords = {routing   topology}
}