1. AS Rank Website. http://as-rank.caida.org/. AS Rank Website. http://as-rank.caida.org/.
2. Autonomous System (AS) Numbers. http://www.iana.org/assignments/as-numbers/as-numbers.xml. Autonomous System (AS) Numbers. http://www.iana.org/assignments/as-numbers/as-numbers.xml.
3. Internet Topology Collection. http://irl.cs.ucla.edu/topology/. Internet Topology Collection. http://irl.cs.ucla.edu/topology/.
4. RIPE (RIS). http://www.ripe.net/ris/. RIPE (RIS). http://www.ripe.net/ris/.
5. U. Oregon Route Views Project. http://www.routeviews.org/. U. Oregon Route Views Project. http://www.routeviews.org/.