@article{DAN_1963_152_1_a1,
     author = {A. I. Achil'diev},
     title = {The first and second boundary-value problems for elliptic equations which are degenerate at a finite number of interior points},
     journal = {Doklady Akademii Nauk},
     pages = {13--16},
     publisher = {mathdoc},
     volume = {152},
     number = {1},
     year = {1963},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1963_152_1_a1/}
}