Covariantization and canonical quantization in the light-cone gauge
  In the light-cone gauge choice for Abelian and non-Abelian gauge fields, the vector boson propagator carries in it an additional ``spurious'' or ``unphysical'' pole intrinsic to the choice requiring a careful mathematical treatment. Research in this field over the years has shown us that mathematical consistency only is not enough to guarantee physically meaningful results. Whatever the prescription invoked to handle such an object, it has to preserve causality in the process. On the other hand the covariantization technique is a well suited one to tackle gauge dependent poles in the Feynman integrals, dispensing the use of {\em ad hoc} prescriptions. In this work we show that the covariantization technique in the light-cone gauge is a direct consequence of the canonical quantization of the theory. 
Alfredo T. Suzuki and Ricardo Bentin