Approximation by Walsh-Kaczmarz-Fej\'er means on the Hardy space
  The main aim of this paper is to find necessary and sufficient conditions for the convergence of Walsh-Kaczmarz-Fej\'er means in the terms of the modulus of continuity on the Hardy spaces $H_{p},$ when $0<p\leq 1/2.$ 
George Tephnadze
math.CA math.FA