@article{MZM_2012_92_4_a4,
     author = {V. M. Dolgopolov and I. N. Rodionova},
     title = {Extremal {Properties} of {Solutions} of {Special} {Classes} of a {Hyperbolic-Type} {Equation}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {533--540},
     publisher = {mathdoc},
     volume = {92},
     number = {4},
     year = {2012},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2012_92_4_a4/}
}