On metrizable abelian groups with a completeness-type property J. Burzyk; C. Kliś; Z. Lipecki — 1984 Colloquium Mathematicae
Borel and monotone hierarchies and extension of Rényi probability spaces B. Aniszczyk; J. Burzyk; A. Kamiński — 1987 Colloquium Mathematicae