@article{FAA_1971_5_4_a9,
     author = {V. I. Gorbachuk and M. L. Gorbachuk},
     title = {Self-adjoint boundary problems with discrete spectrum generated by the {Sturm--Liouville} equation with unbounded operator coefficient},
     journal = {Funkcionalʹnyj analiz i ego prilo\v{z}eni\^a},
     pages = {67--68},
     publisher = {mathdoc},
     volume = {5},
     number = {4},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/FAA_1971_5_4_a9/}
}