@article{MZM_1988_44_1_a0,
     author = {V. I. Arnol'd},
     title = {Surfaces defined by hyperbolic equations},
     journal = {Matemati\v{c}eskie zametki},
     pages = {3--18},
     publisher = {mathdoc},
     volume = {44},
     number = {1},
     year = {1988},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1988_44_1_a0/}
}