%0 Journal Article
%A Zurab Janelidze
%T The pointed subobject functor, 3 x 3 lemmas, and subtractivity of spans
%J Theory and applications of categories
%D 2010
%P 221-242
%V 23
%I mathdoc
%U http://geodesic.mathdoc.fr/item/TAC_2010_23_a10/
%G en
%F TAC_2010_23_a10