Evaluation of hadronic vacuum polarization contribution to muonium   hyperfine splitting
  The contribution of hadronic vacuum polarization (HVP) to the hyperfine splitting of the muonium ground state is evaluated with the account of modern experimental data on the cross section of $e^+e^- \to$ annihilation into hadrons. 
R.N.Faustov, A.Karimkhodzhaev, A.P.Martynenko