Xenofontas A. Dimitropoulos Dmitri V. Krioukov Marina Fomenkov Bradley Huffaker Young Hyun Kimberly C. Claffy George F. Riley AS relationships: inference and validation. 29-40 2007 37 Computer Communication Review 1 http://doi.acm.org/10.1145/1198255.1198259 db/journals/ccr/ccr37.html#DimitropoulosKFHHCR07