Ad. Popov et Cr. Preitschopf, EXTENDED CONFORMAL-SYMMETRIES OF THE SELF-DUAL YANG-MILLS EQUATIONS, Physics letters. Section B, 374(1-3), 1996, pp. 71-79
We describe an infinite-dimensional Kac-Moody-Virasoro algebra of new
hidden symmetries for the self-dual Yang-Mills equations related to co
nformal transformations of the 4-dimensional base space.