@article{VMUMM_1987_1_a6,
     author = {V. V. Borisov},
     title = {Singular perturbations of ordinary differential operators with integral boundary conditions},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {23--26},
     year = {1987},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1987_1_a6/}
}