%0 Journal Article
%A Janusz Pawlikowski
%T A characterization of $\boldsymbol {\Sigma }_{2}^{1}$ sets
%J Fundamenta Mathematicae
%D 2017
%P 45-49
%V 236
%N 1
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.4064/fm61-4-2016/
%R 10.4064/fm61-4-2016
%G en
%F 10_4064_fm61_4_2016