Quantization of Massive Non-Abelian Gauge Fields in The Hamiltonian Path   Integral Formalism
  It is argued that the massive non-Abelian gauge field theory without involving Higgs bosons may be well established on the basis of gauge-invariance principle because the dynamics of the field is gauge-invariant in the physical space defined by the Lorentz constraint condition. The quantization of the field can readily be performed in the Hamiltonian path-integral formalism and leads to a quantum theory which shows good renormalizability and unitarity. 
Jun-Chen Su