@inproceedings{2006-timetree,
  title = {TimeTree: Exploring Time Changing Hierarchies},
  author = {Stuart K. Card AND Bongwon Suh AND Bryan Pendleton AND Jeffrey Heer AND John W. Bodnar},
  booktitle = {IEEE Visual Analytics Science \& Technology (VAST)},
  year = {2006},
  pages = {3--10},
  url = {http://vis.stanford.edu/papers/timetree}
}