00757nam0-22002771i-450-990001135990403321000113599FED01000113599(Aleph)000113599FED0100011359920000920d1959----km-y0itay50------baengOrbit theoryby Birkhoff,Langers.l.American Mathematical Society1959Proceedings of symposia in applied mathematicsIX Vol.Birkhoff,Garrett<1911-1996>13068Langer,ITUNINARICAUNIMARCBK990001135990403321C-49-(94585MA1MA1Orbit theory345166UNINAING01