An Axiomatic Approach to Semiclassical Field Perturbation Theory
  Semiclassical perturbation theory is investigated within the framework of axiomatic field theory. Axioms of perturbation semiclassical theory are formulated. Their correspondence with LSZ approach and Schwinger source theory is studied. Semiclassical S-matrix, as well as examples of decay processes, are considered in this framework. 
O.Yu.Shvedov