@article{MZM_2009_86_6_a1,
     author = {V. V. Grushin},
     title = {Multiparameter {Perturbation} {Theory} of {Fredholm} {Operators} {Applied} to {Bloch} {Functions}},
     journal = {Matemati\v{c}eskie zametki},
     pages = {819--828},
     publisher = {mathdoc},
     volume = {86},
     number = {6},
     year = {2009},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MZM_2009_86_6_a1/}
}