@article{SM_1987_57_2_a0,
     author = {S. A. Nazarov},
     title = {Justification of asymptotic expansions of the eigenvalues of nonselfadjoint singularly perturbed elliptic boundary value problems},
     journal = {Sbornik. Mathematics},
     pages = {317--349},
     publisher = {mathdoc},
     volume = {57},
     number = {2},
     year = {1987},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1987_57_2_a0/}
}