@article{MZM_1974_15_2_a9,
     author = {V. I. Bernik and \'E. I. Kovalevskaya},
     title = {Extremal property of some surfaces in $n$-dimensional {Euclidean} space},
     journal = {Matemati\v{c}eskie zametki},
     pages = {247--254},
     publisher = {mathdoc},
     volume = {15},
     number = {2},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1974_15_2_a9/}
}