Ulrik Brandes Jürgen Lerner Miranda J. Lubbers Chris McCarty José Luis Molina Visual Statistics for Collections of Clustered Graphs. 47-54 2008 PacificVis http://dx.doi.org/10.1109/PACIFICVIS.2008.4475458 conf/apvis/2008 db/conf/apvis/pacificvis2008.html#BrandesLLMM08