As for Schwinger's book on source theory, it is quite terse and his arguments are difficult to follow. If anyone has understood the idea and implementation (mathematical) of source theory, can you provide a succinct mathematical account of the theory and detail whether or not it is actually an alternative to traditional techniques of QFT (read Feynman diagrams and canonical quantization).
closed as too broad by Danu, John Rennie, heather, Kyle Kanos, rob♦ Feb 18 '17 at 2:16
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