Pair Correlations in Scale-Free Networks
  Correlation between nodes is found to be a common and important property in many complex networks. Here we investigate degree correlations of the Barabasi-Albert (BA) Scale-Free model with both analytical results and simulations, and find two neighboring regions, a disassortative one for low degrees and a neutral one for high degrees. The average degree of the neighbors of a randomly picked node is expected to diverge in the limit of infinite network size. As an generalization of the concept of correlation, we also study the correlations of other scalar properties, including age and clustering coefficient. Finally we propose a correlation measurement in bipartite networks. 
Huang Zhuang-Xiong, Wang Xin-Ran and Zhu Han