4[1]Sutherland I E. Sketchpad: A man-machine graphical communication system[A]. In: Proceedings of AFIPS Spring Joint Computer Conference[C], Detroit, Michigan: Spartan Book, 1963. 329～346
5[2]Cutkosky M R. PACT: An experiment in integrating concurrent engineering systems[J]. IEEE Computer, 1993, 26(1):28～37
6[3]Anupam V, Baja C L. Shastra: Multimedia collaborative design environment[J]. IEEE Multimedia, 1994, 1(2):39～49
7[4]Delisle N M, Schwartz M D. Neptune: A hypertext system for CAD applications[A]. In: Zaniolo C ed. Proceedings of ACM SIGMOD'86 International Conference on Management of Data[C], Washington D C: ACM Press, 1986. 132～143
8[5]Schiffner N, Kollmann H. Distributed sketchpad[A]. In: Proceedings of First International Workshop on CSCW in Design[C], Beijing: International Academic Publishers, 1996. 491～499
9[6]Knister M, Praksh A. DistEdit: A distributed toolkit for supporting multiple group editors[A]. In: Proceedings of ACM CSCW'90, Los Angeles, CA, 1990. 343～355
10[7]Reinhard W Schweitzer, Volksen G. CSCW tools: Concepts and architectures[J]. IEEE Computer, 1994, 27(5):28～36
