1. Our notation follows that of and , Relativistic Quantum Fields, McGraw-Hill, New York 1965.
2. Harvard lecture notes, 1954 (unpublished);
3. Über das Schwingersche Funktional in der Feldtheorie
4. Lectures on Particles and Field Theory, Vol. 2, p. 1 (S. Deser and K. W. Ford, eds.).
5. Lectures on Particles and Field Theory Englewood Cliffs: Prentice-Hall, Inc. 1965;