@article{MT_1989_14_a10,
     author = {E. V. Shikin},
     title = {The isometric embedding problem and {Monge--Amp\`ere} equations of hyperbolic type},
     journal = {Matemati\v{c}eskie trudy},
     pages = {245--258},
     publisher = {mathdoc},
     volume = {14},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MT_1989_14_a10/}
}