In　this　paper,　we　study　the　cooperative　output　regulation　problem　for　a　class　of　second-order　linear　uncertain　multi-agent　systems　with　unknown　exosystem.　We　first　present　a　distributed　canonical　internal　model　to　convert　the　cooperative　output　regulation　problem　for　the　original　plant　into　a　stabilization　problem　for　its　augmented　system.　Then　we　solve　the　problem　via　a　distributed　state　feedback　controller　by　combining　the　distributed　internal　model　approach　and　the　adaptive　control　technique.　Our　design　is　illustrated　by　an　example.　©　2014　IEEE.