Politzer, H.D.; Reliable Perturbative Results for Strong Interactions?
Phys. Rev. Lett. 30 (1973) 1346;
Reprinted in The Physical Review - the First Hundred Years, AIP Press (1995) CD-ROM.
An explicit calculation shows perturbation theory to be arbitrarily good for the deep Euclidean Green's functions of any Yang-Mills theory and many Yang-Mills theories with fermions. Under the hypothesis that spontaneous symmetry breakdown is of dynamical origin, these symmetric Green's functions are the asymptotic forms of the physically significant spontaneously broken solution, whose coupling could be strong.
Related references See also S. L. Adler, Phys. Rev. D5 (1972) 3021;
K. Symanzik, preprint DESY-72-73 (1972);
N. N. Bogolyubov and D. V. Shirkov, Introduction to the Theory of Quantized Fields, New York, (1959);
Y. Nambu and G. Jona-Lasinio, Phys. Rev. 122 (1961) 345;
B. W. Lee and J. Zinn Justin, Phys. Rev. D5 (1972) 3121;
G. 't Hooft, Nucl. Phys. B33 (1971) 173;
D. J. Gross and F. Wilczek, Phys. Rev. Lett. 30 (1973) 1343;
S. Coleman and S. Weinberg, Phys. Rev. D7 (1973) 1888;
Discovery of the "asymptotic freedom'' property of interacting Yang-Mills field theories.