Tynnyi V. I.
Ukr. Mat. Zh. - 1993. - 45, № 12. - pp. 1661–1667
For the linear systemof difference equations $x(t + 1) = Ax(t) + P(t)x(t)$, where the matrix $P(t)$ is almost periodic, sufficient conditions are given, which reduce it to a system with a constant matrix.