B.A. Dubrovin, A.T. Fomenko, S.P. Novikov ; translated by Robert G. Burns ; : U.S., : Germany. -- Springer-Verlag, c1984. -- (Graduate texts in mathematics ; 93 . { Modern geometry : methods and applications / B.A. Dubrovin, A.T. Fomenko, S.P. Novikov ; translated by Robert G. Burns } ; pt. 1)(Springer series in Soviet mathematics).