%0 Journal Article %A Czerwik, S. %T Contraction mappings in $b$-metric spaces %J Communications in Mathematics %D 1993 %P 5-11 %V 01 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/COMIM_1993__1_1_a1/ %G en %F COMIM_1993__1_1_a1