TY  - JOUR
AU  - S. Ya. Havinson
TI  - A~Chebyshev theorem for the approximation of a~function of two variables by sums of the type $\varphi(x)+\psi(y)$
JO  - Izvestiya. Mathematics 
PY  - 1969
SP  - 617
EP  - 632
VL  - 3
IS  - 3
PB  - mathdoc
UR  - http://geodesic.mathdoc.fr/item/IM2_1969_3_3_a6/
LA  - en
ID  - IM2_1969_3_3_a6
ER  -