<https://secure.gravatar.com/avatar/bf6cb6767a9f7c4001008c4892ad2290?s=96&amp;d=mm&amp;r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.tuttosullapostaelettronica.it/blog/mail-pacco-in-giacenza/>