@article{2009-protovis,
  title = {Protovis: A Graphical Toolkit for Visualization},
  author = {Michael Bostock AND Jeffrey Heer},
  journal = {IEEE Trans. Visualization \& Comp. Graphics (Proc. InfoVis)},
  year = {2009},
  url = {http://vis.stanford.edu/papers/protovis}
}