@article{Łenski:2007,
  author  = "W. Łenski",
  title   = "Pointwise strong and very strong approximation of Fourier series",
  journal = "Acta Mathematica Hungarica",
  volume  = "Vol. 115",
  number  = "no 3",
  pages   = "215--233",
  year    = "2007",
}