Quantum Field Theory and the Standard Model by Schwartz M.D. z-lib.org · Problem 6.2
The S-matrix and time-ordered products — Schwartz M.D. z-lib.org
Physics — QFT · advanced-retarded-propagators
The S-matrix and time-ordered products — Schwartz M.D. z-lib.org
Physics — QFT · advanced-retarded-propagators