On Symmetric Gauge Fields for arbitrary Gauge and Symmetry Groups
  A classification of the possible symmetric principal bundles with a compact gauge group, a compact symmetry group and a base manifold which is regularly foliated by the orbits of the symmetry group is derived. A generalization of Wang's theorem (classifying the invariant connections) is proven and local expressions for the gauge potential of an invariant connection are given. 
Othmar Brodbeck