1. Atiyah, M.F., Bott, R.: The Yang-Mills equations over Riemann surfaces. Phil Trans. R. Soc. Lond. A308, 523–615 (1982)
2. Friedrich, Th., Habermann, L.: Yang-Mills equations on the two-dimensional sphere. Commun. Math. Phys.100, 231–243 (1985)
3. Nahm, W., Uhlenbeck, K.: The equivalence of quantized gauge fields onS 2 and the quantum mechanics of a particle moving on the group manifold. Preprint
4. Pressley, A., Segal, G.: Loop groups. Oxford: Clarendon Press 1986
5. Seeley, R.T.: Extensions ofC ∞-functions defined in a half space. Proc. Am. Math. Soc.15, 625–626 (1964)