@article{Leśniewski:2009,
author
=
"P.Leśniewski and A.Wiśniewski",
title
=
"Reducibility of questions to sets of guestions: some feasibility results",
journal
=
"Logique & Analyse",
number
=
"vol. 173-174-175",
pages
=
"93--111",
year
=
"2001",
}