1. CAIDA, the Cooperative Association for Internet Data Analysis. http://www.caida.org/.
2. NLANR Global ISP interconnectivity by AS number. http://moat.nlanr.net/AS/.
3. TIERS. http://www.isi.edu/haldar/topogen/tiers.
4. University of Oregon route views project. http://antc.uoregon.edu/route-views/.
5. AT&T IP backbone. http://www.ipservices.att.com/backbone/, 2001.