@article{DAN_1987_293_2_a18,
     author = {N. S. Kellin},
     title = {Conditionally stationary initial-boundary value problems in},
     journal = {Doklady Akademii Nauk},
     pages = {339--342},
     publisher = {mathdoc},
     volume = {293},
     number = {2},
     year = {1987},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1987_293_2_a18/}
}