command that can display routes containing AS loops

Hi everyone, I am curious about the AS loops in the AS-path. I think there should be a very, very few received BGP routes that contain the local AS#. But because such routes will be dropped and not installed in Loc-RIB, I want to know if there is a command that can display the dropped routes containing AS loops (in cisco or juniper router). Does anybody know? Thanks! Best! -- Song Li Room 4-204, FIT Building, Network Security, Department of Electronic Engineering, Tsinghua University, Beijing 100084, China Tel:( +86) 010-62446440 E-mail: refresh.lsong@gmail.com