Fernanda B. Viégas Martin Wattenberg Frank van Ham Jesse Kriss Matthew M. McKeon 1121-1128 2007 13 IEEE Trans. Vis. Comput. Graph. 6 http://doi.ieeecomputersociety.org/10.1109/TVCG.2007.70577 db/journals/tvcg/tvcg13.html#ViegasWHKM07