<https://secure.gravatar.com/avatar/5d7669c4b47573f9d1eeabf8e49f45ce?s=96&d=mm&r=g>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.comosoft.us/blog/the-future-of-black-friday-for-retailers/>