@article{MZM_1992_52_4_a5,
     author = {R. R. Gadyl'shin},
     title = {Ramification of a multiple eigenvalue of the {Dirichlet} problem for the {Laplacian} under singular perturbation of the boundary condition},
     journal = {Matemati\v{c}eskie zametki},
     pages = {42--55},
     publisher = {mathdoc},
     volume = {52},
     number = {4},
     year = {1992},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_1992_52_4_a5/}
}