1. D. Alevras, M. Grötschel, and R. Wessäly, Capacity and survivability models for telecommunications networks, Tech. Report SC 97-24, Konrad-Zuse-Zentrum für Informationstechnik, Berlin, 1997.
2. K. Aardal, M. Labbé, J. Leung, and M. Queyranne, On the two-level uncapacitated facility location problem, INFORMS Journal on Computing 8 (1996), 289–301.
3. W. Ben-Ameur and E. Gourdin, Internet routing and related topology issues, SIAM Journal on Discrete Mathematics 17 (2003), 18–49.
4. W. Ben-Ameur, E. Gourdin, and B. Liau, Internet routing and topology problems, Proceedings of DRCN2000 (Munich), 2000.
5. D. Bienstock, S. Chopra, O. Günlük, and C-Y. Tsai, Minimum cost capacity installation for multicommodity network flows, Mathematical Programming 81 (1998), 177–199.