TY  - JOUR
AU  - E. I. Znak
TI  - Operator $Af = f\circ\varphi-f$ in tasks of mathematical competitions
JO  - Matematičeskoe obrazovanie
PY  - 2021
SP  - 23
EP  - 30
VL  - 97
IS  - 1
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/MO_2021_97_1_a4/
LA  - ru
ID  - MO_2021_97_1_a4
ER  -