@article{DAN_1974_218_3_a5,
     author = {\`E. M. Saak},
     title = {Duality theorems for a problem with oblique derivative},
     journal = {Doklady Akademii Nauk},
     pages = {521--524},
     publisher = {mathdoc},
     volume = {218},
     number = {3},
     year = {1974},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1974_218_3_a5/}
}