Analytic properties of Feynman diagrams in quantum field theory /
Todorov, Ivan T.
Risk, Clifford.
Oxford Pergamon
1971
Revised translation of 'Analiticheskie svoistva diagramm Feinmana v kvantovoi teorii polia'. Sofiia: Izd-vo Bolgarskoi Akademii Nauk, 1966
bibl p140-149
Feynman diagrams.
Perturbation (Quantum dynamics)
Dispersion relations.
Particles (Nuclear physics)