@article{VMUMM_1990_6_a23,
     author = {A. N. Yakivchik},
     title = {On the diagonal number of topological spaces},
     journal = {Vestnik Moskovskogo universiteta. Matematika, mehanika},
     pages = {84--86},
     publisher = {mathdoc},
     number = {6},
     year = {1990},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/VMUMM_1990_6_a23/}
}