Representations of the group of functions taking values in a compact Lie group I. M. Gelfand; M. I. Graev; A. M. Veršik — 1980 Compositio Mathematica
Representations of the group of smooth mappings of a manifold X into a compact Lie group I. M. Gelfand; M. I. Graev; A. M. Verťik — 1977 Compositio Mathematica