Closed geodesics on surfaces of genus 0
Page 1
Wilhelm Klingenberg (1979)
Annali della Scuola Normale Superiore di Pisa - Classe di Scienze
Smoczyk, Knut (2003)
The New York Journal of Mathematics [electronic only]
Karsten Grove, Stephen Halperin (1982)
Publications Mathématiques de l'IHÉS
Halldór I. Elíasson (1974)
Mathematische Zeitschrift
B. White (1987)
Inventiones mathematicae
Page 1