Curve shortening on surfaces Michael E. Gage (1990) Annales scientifiques de l'École Normale Supérieure
Cusp closing in rank one symmetric spaces. Viktor Schroeder, Christoph Hummel (1996) Inventiones mathematicae
Cut loci of closed surfaces without conjugate points David D. Bleecker (1981) Colloquium Mathematicae
Cut locus and parallel circles of a closed curve on a Riemannian plane admitting total curvature. Katsuhiro Shiohama (1985) Commentarii mathematici Helvetici