@article{MO_2017_1_a4,
     author = {E. I. Znak},
     title = {Operators of the type $Af(x)=f(a{\cyrh}+b)-\lambda f(x)$ and functional equations in problems of math competitions},
     journal = {Matemati\v{c}eskoe obrazovanie},
     pages = {33--39},
     year = {2017},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MO_2017_1_a4/}
}