@article{DE_2000_36_4_a5,
     author = {K. V. Kravchenko},
     title = {Differential operators with nonlocal boundary conditions},
     journal = {Differencialʹnye uravneni\^a},
     pages = {464--469},
     publisher = {mathdoc},
     volume = {36},
     number = {4},
     year = {2000},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_2000_36_4_a5/}
}