@article{TIMM_2011_17_3_a20,
     author = {A. A. Koshelev},
     title = {The best $L_p$ approximation of the {Laplace} operator by linear bounded operators in the classes of functions of two and three variables},
     journal = {Trudy Instituta matematiki i mehaniki},
     pages = {217--224},
     publisher = {mathdoc},
     volume = {17},
     number = {3},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TIMM_2011_17_3_a20/}
}