@article{ZNSL_1989_170_a14,
     author = {P. L. Ul'yanov},
     title = {On some results and problems in the theory of bases},
     journal = {Zapiski Nauchnykh Seminarov POMI},
     pages = {274--284},
     publisher = {mathdoc},
     volume = {170},
     year = {1989},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/ZNSL_1989_170_a14/}
}