@article{FAA_1980_14_4_a7,
     author = {V. A. Babets},
     title = {A hyperbolicity theorem},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {61},
     publisher = {mathdoc},
     volume = {14},
     number = {4},
     year = {1980},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1980_14_4_a7/}
}