SPACES WITH NON-POSITIVE CURVATURE

[1] BERWALD L, 1941, FINSLERSCHE CARTANSC, V17, P34

[2] Bolza Oscar., 1909, VORLESUNGEN VARIATIO

[3] THE ISOPERIMETRIC PROBLEM IN THE MINKOWSKI PLANE [J]. AMERICAN JOURNAL OF MATHEMATICS, 1947, 69 (04) : 863 - 871

[4] INTRINSIC AREA [J]. ANNALS OF MATHEMATICS, 1947, 48 (02) : 234 - 267

[5] BUSEMANN H, 1942, ANN MATH STUDIES, V8

[6] Local metric geometry [J]. TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY, 1944, 56 (1-3) : 200 - 274

[7] CARTAN E, 1928, LECONS GEOMETRIE SUR

[8] Cohn-Vossen S., 1935, COMPOS MATH, V2, P69

[9] HADAMARD J, 1898, J MATH PURE APPL, V4, P27

[10] HOPF H, 1932, MATH ANN, V107, P113

[1] BERWALD L, 1941, FINSLERSCHE CARTANSC, V17, P34

[2] Bolza Oscar., 1909, VORLESUNGEN VARIATIO

[3] THE ISOPERIMETRIC PROBLEM IN THE MINKOWSKI PLANE [J]. AMERICAN JOURNAL OF MATHEMATICS, 1947, 69 (04) : 863 - 871

[4] INTRINSIC AREA [J]. ANNALS OF MATHEMATICS, 1947, 48 (02) : 234 - 267

[5] BUSEMANN H, 1942, ANN MATH STUDIES, V8

[6] Local metric geometry [J]. TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY, 1944, 56 (1-3) : 200 - 274

[7] CARTAN E, 1928, LECONS GEOMETRIE SUR

[8] Cohn-Vossen S., 1935, COMPOS MATH, V2, P69

[9] HADAMARD J, 1898, J MATH PURE APPL, V4, P27

[10] HOPF H, 1932, MATH ANN, V107, P113