@article{ZNSL_1981_113_a15,
     author = {V. G. Maz'ya},
     title = {Extension of functions from {Sobolev} spaces},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {231--236},
     publisher = {mathdoc},
     volume = {113},
     year = {1981},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1981_113_a15/}
}