<https://secure.gravatar.com/avatar/71f4982db39c36a8b4e0f66814a52bc1?s=96&amp;d=mm&amp;r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://fiodevida.com/como-usar-o-zello-um-aplicativo-push-to-talk/>