%0 Journal Article
%A J. Paris
%A G. Mills
%T Closure properties of countable non-standard integers
%J Fundamenta Mathematicae
%D 1979
%P 205-215
%V 103
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/articles/10.4064/fm-103-3-205-215/
%R 10.4064/fm-103-3-205-215
%G en
%F 10_4064_fm_103_3_205_215