World Line Path Integrals as a Calculational Tool in Quantum Field   Theory
  We report on the status of the string-inspired world line path integral formalism, a recently developed powerful tool for the reorganisation of standard perturbative amplitudes in quantum field theory. The method is outlined and the present range of its applicability surveyed. The emphasis is on QED and QCD photon/gluon amplitudes, with a short discussion of axial couplings. 
Michael G. Schmidt, Christian Schubert