TY  - JOUR
TI  - Yuri\u{\i} Leonidovich Ershov (on the occasion of his fiftieth               birthday)
JO  - Algebra i logika
PY  - 1990
SP  - 135
EP  - 138
VL  - 29
IS  - 2
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/AL_1990_29_2_a0/
LA  - ru
ID  - AL_1990_29_2_a0
ER  -