Wolfram Demonstrations Projecthttp://demonstrations.wolfram.com/An Open Resource of Interactive Mathematica VisualizationsCopyright 2009 Wolfram Demonstrations Project & ContributorsPT-symmetric Quantum Walks and Centrality Testing on Directed Graphshttp://demonstrations.wolfram.com/PTSymmetricQuantumWalksAndCentralityTestingOnDirectedGraphs/]]>http://demonstrations.wolfram.com/PTSymmetricQuantumWalksAndCentralityTestingOnDirectedGraphs/