1. Integralfreie Variationsrechnung ttingen;Siegel;Math phys,1957
2. Quasigeodesics on convex surfaces;Pogorelov;Math,1962
3. Existence of infmitely many closed geodesics;Klingenberg;Geom,1976
4. Geodesics on typical convex surfaces Atti Accad Rend to appear;Gruber;Natur,1988
5. Equivalent Morse theory and closed geodesics;Hingston;Geom,1984