3CHEN C. Searching for intellectual turning points: progres- sive knowledge domain visualization[J]. Proceedings of the National Academy of Sciences, 2004,101 (Suppl 1 ) :5303- 5310.
4CHEN C. Cite Space II: detecting and visualizing emerging trends and transient patterns in scientific literature [J]. Jour- nal of the American Society for Information Science and Technology, 2006,57 (3), 359-377.