TY  - JOUR
AU  - I. I. Parovichenko
TI  - Certain special classes of topological spaces and $\delta s$-operations
JO  - Doklady Akademii Nauk
PY  - 1957
SP  - 866
EP  - 868
VL  - 115
IS  - 5
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1957_115_5_a3/
LA  - ru
ID  - DAN_1957_115_5_a3
ER  -