@article{DAN_1968_179_2_a8,
     author = {G. I. Laptev},
     title = {Boundary value problems for second order differential equations in {Hilbert} space with a variable selfadjoint operator},
     journal = {Doklady Akademii Nauk},
     pages = {283--286},
     publisher = {mathdoc},
     volume = {179},
     number = {2},
     year = {1968},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1968_179_2_a8/}
}