M. Consens, A. Mendelzon, and A. Ryman. International Conference on Software Engineering, page 138 - 156. Melbourne, Australia, IEEE, (11--15 May 1992)
M. Storey, D. Cubranic, and D. German. SoftVis '05: Proceedings of the 2005 ACM symposium on Software visualization, page 193--202. St Louis, MS, ACM Press, (2005)