Kinnersley-type representation is constructed for the four-dimensional EinsteinMaxwell-dilaton-axion system restricted to space-times possessing two non-null commuting Killing symmetries. New representation essentially uses the matrixvalued SL(2, R) formulation and effectively reduces the construction of the Geroch group to the corresponding problem for the vacuum Einstein equations. An infinite hierarchy of potentials is introduced in terms of 2 × 2 real symmetric matrices directly generalizing the scalar hierarchy of Kinnersley-Chitre known for the vacuum Einstein equations. PASC number(s): 97.60.Lf, 04.60.+n, 11.17.+y 1 A talk given at