Spaces of functions of mixed smoothness and approximation from hyperbolic crosses. - Hans-Jürgen Schmeißer; Winfried Sickel (J. Approx. Theory, 2004)

Besov spaces with generalized smoothness and summability of multiple Fourier series. - S. Artamonov; K. V. Runovski; Hans-Jürgen Schmeißer (J. Approx. Theory, 2022)