%0 Journal Article %A Leo Marcus %T The number of countable models of a theory of one unary function %J Fundamenta Mathematicae %D 1980 %P 171-181 %V 108 %N 3 %I mathdoc %U http://geodesic.mathdoc.fr/articles/10.4064/fm-108-3-171-181/ %R 10.4064/fm-108-3-171-181 %G en %F 10_4064_fm_108_3_171_181