Trend Graphs: Visualizing the Evolution of Concept Relationships in Large Document Collections. - Ronen Feldman; Yonatan Aumann; Amir Zilberstein; Yaron Ben-Yehuda (PKDD, 1998)

Circle Graphs: New Visualization Tools for Text-Mining. - Yonatan Aumann; Ronen Feldman; Yaron Ben-Yehuda; David Landau; Orly Liphstat; Yonatan Schler (PKDD, 1999)