Simpleicon Business by SimpleIcon
<a rel="nofollow" class="external text" href="http://www.simpleicon.com/">SimpleIcon</a>
CC BY 3.0
<a rel="nofollow" class="external free" href="http://www.flaticon.com/packs/simpleicon-business">http://www.flaticon.com/packs/simpleicon-business</a>