Observation of Z decays to four leptons with the CMS detector at the LHC
JHEP 1212 (2012) 034
The collaboration

Abstract (data abstract)
CERN-LHC. A measurement is presented of the Z cross section in the Z-> 4l decay mode with l = e, mu in proton-proton collisions at sqrt(s) = 7 TeV with the CMS experiment at the LHC. Results are based on data corresponding to an integrated luminosity of 5.0 fb-1. The measured cross section is consistent with the standard model prediction of 120 fb.