@article{TSP_2011_28_28_a7,
     author = {P. I. Kaleda},
     title = {Singular systems on the plane and in space},
     journal = {Trudy Seminara im. I.G. Petrovskogo},
     pages = {204--228},
     publisher = {mathdoc},
     volume = {28},
     number = {28},
     year = {2011},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TSP_2011_28_28_a7/}
}