@article{DAN_1986_289_5_a7,
     author = {N. I. Popivanov},
     title = {Nonlocal regularization of boundary value problems for the wave},
     journal = {Doklady Akademii Nauk},
     pages = {1060--1063},
     year = {1986},
     volume = {289},
     number = {5},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1986_289_5_a7/}
}