@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://idl.cs.washington.edu/papers/protovis},
}