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@article{MZM_1983_34_4_a6, author = {V. I. Feigin}, title = {Decrease of the lengths of the gaps in the spectrum of polynomial pencils}, journal = {Matemati\v{c}eskie zametki}, pages = {549--557}, publisher = {mathdoc}, volume = {34}, number = {4}, year = {1983}, language = {ru}, url = {http://geodesic.mathdoc.fr/item/MZM_1983_34_4_a6/} }
V. I. Feigin. Decrease of the lengths of the gaps in the spectrum of polynomial pencils. Matematičeskie zametki, Tome 34 (1983) no. 4, pp. 549-557. http://geodesic.mathdoc.fr/item/MZM_1983_34_4_a6/