@article{DE_1976_12_10_a1,
     author = {V. F. Butuzov and N. N. Nefedov},
     title = {A problem in the theory of singular perturbations},
     journal = {Differencialʹnye uravneni\^a},
     pages = {1736--1747},
     publisher = {mathdoc},
     volume = {12},
     number = {10},
     year = {1976},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1976_12_10_a1/}
}