The Women's nubuck Uno - the white, pink, and black - run true to size or small.  If in doubt, order a half-size up.  The Women's Silver Uno is made with leather that is 0.5 mm thicker than the nubuck, so we definitely recommend ordering a half-size up.

 US 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10 10.5 11
Italy 35.5 36 36.5 37 37.5 38 38.5 39 39.5 40 40.5 41
UK 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8
Japan 22.5 23 23.5 24 24.5 25 25.5 26 26.5 27 27.5 28