TY  - JOUR
AU  - N. G. Parvatov
TI  - Lower and upper neighborhoods in set with closure property
JO  - Prikladnaâ diskretnaâ matematika
PY  - 2009
SP  - 5
EP  - 13
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/PDM_2009_3_a0/
LA  - ru
ID  - PDM_2009_3_a0
ER  -