A. Kerren, F. Breier, P. Kügler:
"DGCVis: An Exploratory 3D Visualization of Graph Pyramids. ";
in: "Proceedings of the 2nd International Conference on Coordinated and Multiple Views in Exploratory Visualization (CMV '04)", IEEE, 2004, 73 - 83.
http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC04968666