@MISC{Hadlak10SpaceTimeHierarchies,
  author = {Steffen Hadlak and Christian Tominski and Hans-Jörg Schulz and Heidrun
	Schumann},
  title = {{Visualization of Hierarchies in Space and Time}},
  howpublished = {Workshop GeoVA(t) - Geospatial Visual Analytics: Focus on Time at
	the AGILE International Conference on Geographic Information Science},
  year = {2010},
  location = {Guimarães, Portugal}
}