@article{VMUMM_2004_1_a0,
     author = {S. A. Bogatyi and O. D. Frolkina},
     title = {Isometricity of mappings preserving perimeter},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {3--11},
     publisher = {mathdoc},
     number = {1},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_2004_1_a0/}
}