%0 Journal Article
%A Umar, Abdullahi
%T Presentations for subsemigroups of $PD_n$
%J Czechoslovak Mathematical Journal
%D 2019
%P 417-426
%V 69
%N 2
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.21136/CMJ.2018.0343-17/
%R 10.21136/CMJ.2018.0343-17
%G en
%F 10_21136_CMJ_2018_0343_17