@article{DE_1990_26_2_a11,
     author = {V. F. Butuzov and A. G. Nikitin},
     title = {A singularly perturbed system of equations of elliptic type},
     journal = {Differencialʹnye uravneni\^a},
     pages = {271--278},
     publisher = {mathdoc},
     volume = {26},
     number = {2},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DE_1990_26_2_a11/}
}