@article{MZM_1980_28_3_a5,
     author = {L. V. Bogachev},
     title = {Trace of the {Sturm{\textendash}Liouville} operator with nonlocal boundary conditions},
     journal = {Matemati\v{c}eskie zametki},
     pages = {379--390},
     year = {1980},
     volume = {28},
     number = {3},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1980_28_3_a5/}
}