@article{VNGU_2007_7_2_a4,
     author = {A. I. Parf\"enov},
     title = {On the existence of a contraction mapping preserving boundary values},
     journal = {Sibirskij \v{z}urnal \v{c}istoj i prikladnoj matematiki},
     pages = {65--87},
     publisher = {mathdoc},
     volume = {7},
     number = {2},
     year = {2007},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VNGU_2007_7_2_a4/}
}