Esfera fondo wiki
<a href="//commons.wikimedia.org/wiki/User:Gustavo_Girardelli" title="User:Gustavo Girardelli">Gustavo Girardelli</a>
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<span class="int-own-work" lang="en">Own work</span> derivado de <a href="//commons.wikimedia.org/wiki/File:Sphere_rotating_transparency.gif" title="File:Sphere rotating transparency.gif">Sphere rotating transparency</a> de <a href="//commons.wikimedia.org/wiki/User:Gustavo_Girardelli" title="User:Gustavo Girardelli">Gustavo Girardelli</a>