  It is well-known that the chiral WZNW Bloch waves satisfy a quadratic
classical exchange algebra which implies the affine Kac-Moody algebra for the
corresponding currents. We here obtain a direct derivation of the exchange
algebra by inverting the symplectic form on the space of Bloch waves, and give
a completely algorithmic construction of its generalized free field
realizations that extend the classical Wakimoto realizations of the current
algebra.
