“…However, J. Marcinkiewicz proved the almost everywhere convergence of these "strong means" for each f ∈ L 1 (T) (see [175,Vol.2,Ch.XIII,§8] or [4, Ch.VII, §8]). There are essential generalizations of strong summability on T n in [45] and [78]. Let {ν m } ∞ m=0 be a strictly increasing sequence of natural numbers.…”