@inproceedings{2002-separating-the-swarm,
  title = {Separating the Swarm: Categorization Methods for User Sessions on the Web},
  author = {Jeffrey Heer AND Ed H. Chi},
  booktitle = {ACM Human Factors in Computing Systems (CHI)},
  year = {2002},
  pages = {243--250},
  url = {http://vis.stanford.edu/papers/separating-the-swarm}
}