V. Batagelj, and M. Zaversnik. Proceedings of the Graph Drawing: 7th International Symposium (GD'99), volume 1731 of LNCS, page 90-98. Stirín Castle, Czech Republic, Springer-Verlag, (September 1999)
V. Batagelj, A. Mrvar, and M. Zaversnik. GD '99: Proceedings of the 7th International Symposium on Graph Drawing, page 90--97. London, UK, Springer-Verlag, (1999)