@article{Łenski:2009,
author
=
"W.Łenski",
title
=
"Strong approximation of functions by the triangular partial sums of double Fourier series",
journal
=
"Demonstratio Mathematica",
volume
=
"Vol. 12",
number
=
"no 2",
pages
=
"445--456",
year
=
"1979",
}