1. A.D. Alexandrov. A theorem on triangles in a metric space and some applications of it. Tr. Mat. Inst. Steklova38, 5–23, 1951. (Russian).
2. A.D. Alexandrov and Yu, D. Burago Quasigeodesics. Proc. Steklov. Inst. Math.76, 58–76, 1965.
3. A.D. Alexandrov and V.V. Strel’tsov. The isoperimetric problem and estimates of a length of a curve on a surface. Proc. Steklov. Inst. Math.76, 81–99, 1965.
4. A.D. Alexandrov and V.A. Zalgaller. Intrinsic geometry of surfaces. Transi. Math. Monographs 15, Am. Math. Soc., 1967.
5. V. Arnold. Lecture given at the meeting in the Fields institute dedicated to his 60th birthday.