@article{MZM_1990_48_1_a9,
     author = {\"U. G. Lumiste},
     title = {Absence of complete {Lobachevskii} planes in two classes of surfaces in~$E_4$ with~$K=-1$},
     journal = {Matemati\v{c}eskie zametki},
     pages = {68--74},
     publisher = {mathdoc},
     volume = {48},
     number = {1},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1990_48_1_a9/}
}