@article{AL_2004_43_4_a2,
     author = {V. L. Selivanov},
     title = {Difference {Hierarchy} in $\varphi${-Spaces}},
     journal = {Algebra i logika},
     pages = {425--444},
     publisher = {mathdoc},
     volume = {43},
     number = {4},
     year = {2004},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AL_2004_43_4_a2/}
}