TY  - JOUR
AU  - I. I. Parovichenko
TI  - On the structure of a class of set-theoretic operations
JO  - Doklady Akademii Nauk
PY  - 1977
SP  - 272
EP  - 275
VL  - 237
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1977_237_2_a4/
LA  - ru
ID  - DAN_1977_237_2_a4
ER  -