@article{ZNSL_1971_22_a7,
     author = {N. K. Nikol'skii},
     title = {The stability of the unicellularity for analytic perturbations ot the class~$\Omega_0^+$},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {89--93},
     publisher = {mathdoc},
     volume = {22},
     year = {1971},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1971_22_a7/}
}