James Abello Stephen G. Kobourov Roman Yusufov Visualizing Large Graphs with Compound-Fisheye Views and Treemaps. 431-441 http://springerlink.metapress.com/openurl.asp?genre=article&issn=0302-9743&volume=3383&spage=431 2004 conf/gd/2004 Graph Drawing db/conf/gd/gd2004.html#AbelloKY04