Daniel Archambault Tamara Munzner David Auber GrouseFlocks: Steerable Exploration of Graph Hierarchy Space. 900-913 2008 14 IEEE Trans. Vis. Comput. Graph. 4 http://dx.doi.org/10.1109/TVCG.2008.34 db/journals/tvcg/tvcg14.html#ArchambaultMA08