@article{RM_1962_17_6_a7,
     author = {V. G. Maz'ya and P. E. Sobolevskii},
     title = {On generating operators of semi-groups},
     journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova},
     publisher = {mathdoc},
     volume = {17},
     number = {6},
     year = {1962},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/RM_1962_17_6_a7/}
}