@article{ZhouKurths2006,
  author    = {Changsong Zhou and J{\"u}rgen Kurths},
  title     = {Hierarchical synchronization in complex networks with heterogeneous degrees},
  doi       = {10.1063/1.2150381},
  url       = {http://scitation.aip.org/getpdf/servlet/ GetPDFServlet?filetype=pdf\&id=CHAOEH000016000001015104000001\&idtype=cvips\&doi=10.1063/1.2150381\&prog=normal},
  year      = {2006},
}