@article{SM_1976_29_1_a2,
     author = {P. L. Ul'yanov},
     title = {On a~countable base and the conjugate class of a~topological space},
     journal = {Sbornik. Mathematics},
     pages = {13--33},
     publisher = {mathdoc},
     volume = {29},
     number = {1},
     year = {1976},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/SM_1976_29_1_a2/}
}