Closed geodesics on surfaces of genus 0 Wilhelm Klingenberg (1979) Annali della Scuola Normale Superiore di Pisa - Classe di Scienze
Closed Legendre geodesics in Sasaki manifolds. Smoczyk, Knut (2003) The New York Journal of Mathematics [electronic only]
Contributions of rational homotopy theory to global problems in geometry Karsten Grove, Stephen Halperin (1982) Publications Mathématiques de l'IHÉS
Convergence of Gradient Curves on Hilbert Manifolds. Halldór I. Elíasson (1974) Mathematische Zeitschrift
Curvature estimates and compactness theorems in 3-manifolds for surfaces that are stationary for parametric elliptic functionals. B. White (1987) Inventiones mathematicae