TY  - JOUR
AU  - G. P. Gavrilov
TI  - On the cardinality of sets of closed classes of finite height in $P_{\aleph_0}$
JO  - Doklady Akademii Nauk
PY  - 1964
SP  - 503
EP  - 506
VL  - 158
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/DAN_1964_158_3_a0/
LA  - ru
ID  - DAN_1964_158_3_a0
ER  -