Feynman rules for the Higgs model

As is well known the standard Dyson formula has to be modified in non-linear and gauge theories.!) In the effective Lagrangian that is employed in the modified Dyson formula we generally have, in additional to the interaction Lagrangian, an extra term involving spurious fields or a highly singular factor i(J 4 (0) . These modified effective Lagrangians are usually derived through the functional or path integration technique.!)