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@article{CMH_1983__58_139948, author = {W. Ballmann and G. Thorbergsson}, title = {Some existence theorems for closed geodesics.}, journal = {Commentarii mathematici Helvetici}, pages = {416--432}, publisher = {mathdoc}, volume = {58}, year = {1983}, zbl = {0532.53034}, url = {http://geodesic.mathdoc.fr/item/CMH_1983__58_139948/} }
W. Ballmann; G. Thorbergsson. Some existence theorems for closed geodesics.. Commentarii mathematici Helvetici, Tome 58 (1983), pp. 416-432. http://geodesic.mathdoc.fr/item/CMH_1983__58_139948/