SurfNet2015-07-022015-07-022014-01http://hdl.handle.net/1880/50533Attribution Non-Commercial Share-Alike 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-sa/4.0/CAPTCHAs for Smartphone UsageDimpVisdirect manipulation techniqueSurfNet Newsletter January 2014Other10.11575/PRISM/35586