Is it OK to mix and distribute data licensed under CC0 and Public Domain?
<p>I would like to create an style-unified collection of cartographic symbols - mainly for use with free SW like QGIS.</p>

<p>I would like to use (probably modify) some already prepared ones from various CC0 licensed sources like <a href="http://www.sjjb.co.uk/mapicons/introduction" rel="nofollow">SJJB icons</a> or <a href="https://www.mapbox.com/maki-icons/" rel="nofollow">Maki icons</a> but also some from <a href="https://openclipart.org/share" rel="nofollow">OpenClipart Library</a></p>

<p>Am I right if I think that I can freely mix and modify distributed content without need to cite sources for particular icons? I plan to keep the CC0 1.0 Universal (CC0 1.0) Public Domain Dedication license even for my original additional icons to not to restrict use in any way and I plan to add something like "<em>Some icons are from source 1), some from source 2)</em>" etc. - just to be fair.</p>

<p>Is it OK?</p>

<p>thanks</p>

<p>If they are licensed under CC0 it is impossible to infringe their copyright.</p>

<p>You have the same rights as if they were public domain due to age.</p>

public-domain