This　paper　studies　cooperative　global　output　regulation　of　a　class　of　heterogeneous　second-order　nonlinear　multi-agent　systems.　The　agents　states　stand　for　positions　and　velocities　and　their　dynamics　can　be　heterogeneous　and　nonlinear,　containing　unknown　parametric　uncertainties.　In　particular,　we　show　solvability　of　the　problem　in　the　situation　of　unknown　exosystems　or　leaders.　Based　on　a　nonlinear　internal　model　principle,　we　develop　an　integral　input-to-state　stability　(iISS)　based　Lyapunov　method　for　a　constructive　nonlinear　feedback　protocol　design.