Salam, A.; Ward, J.C.; On a Gauge Theory of Elementary Interactions
Nuovo Cim. 19 (1961) 165;
Reprinted in Selected papers of Abdus Salam, editor A. Ali et al., p. 195-200..
Gauge theory of weak and electromagnetic interactions, eidtor C. H. Lai, p. 62-67.
A theory of strong as well as weak interactions is proposed using the idea of having only such interactions which arise from generalized gauge transformation.
Related references More (earlier) information appears in A. Salam and J. C. Ward, Nuovo Cim. 11 (1959) 568;
See also J. Tiomno, Nuovo Cim. 6 (1957) 69;
M. Gell-Mann and M. Levi, Nuovo Cim. 16 (1960) 705;
J. J. Sakurai, Ann.Phys. 11 (1960) 1;
J. Schwinger, Ann.Phys. 2 (1957) 407;
Invention of the gauge principle as basis to construct quantum theories of interacting fundamental fields.