Catherine Plaisant Georges G. Grinstein Jean Scholtz Mark Whiting Theresa O'Connell Sharon J. Laskowski Lynn Chien Annie Tat William Wright Carsten Görg Zhicheng Liu Neel Parekh Kanupriya Singhal John T. Stasko 12-21 2008 28 IEEE Computer Graphics and Applications 2 http://doi.ieeecomputersociety.org/10.1109/MCG.2008.27 db/journals/cga/cga28.html#PlaisantGSWOLCTWGLPSS08