Yang, C.N.; Mills, R.L.; Conservation of Isotopic Spin and Isotopic Gauge Invariance
Phys. Rev. 96 (1954) 191;

Reprinted in The Physical Review - the First Hundred Years, AIP Press (1995) 1008.

Abstracts
It is pointed out that the usual principle of invariance under isotopic spin rotation is not consistent with the concept of localized fields. The possibility is explored of having invariance under local isotopic spin rotations. This leads to formulating a principle of isotopic gauge invariance and the existence of a b field which has the same relation to the isotopic spin that the electromagnetic field has to the electric charge. The b field satisfies nonlinear differential equations.
The quanta of the b field are particles with spin unity, isotopic spin unity, and electric charge ± e or zero.

Related references See also F. J. Dyson, Phys. Rev. 75 (1949) 1736;
F. J. Dyson, Phys. Rev. 75 (1949) 486;
E. P. Wigner, Phys. Rev. 51 (1937) 106;
B. Cassen and E. U. Condon, Phys. Rev. 50 (1936) 846;
M. Gell-Mann, Phys. Rev. 92 (1953) 833;
G. Breit, E. U. Condon, and R. D. Present, Phys. Rev. 50 (1936) 825;
J. Schwinger, Phys. Rev. 76 (1949) 790;
W. Pauli, Rev. of Mod. Phys. 13 (1941) 203;
W. Heisenberg and W. Pauli, Z. Phys. 56 (1929) 1;
W. Heisenberg, Z. Phys. 77 (1932) 1;
Analyse data from D. R. Inglis, Rev. of Mod. Phys. 25 (1953) 390;
C. C. Lauritsen, Ann. Rev. Nucl. Sci. 1 (1952) 67;
R. H. Hildebrand, Phys. Rev. 89 (1953) 1090;

Record comments
Introduction of local gauge isotopic spin invariance in quantum field theory: Yang-Mills theory.