<https://forums.egullet.org/topic/148604-blacklisting-culturally-bad-tippers/#comment-1971668>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://forums.egullet.org/topic/148604-blacklisting-culturally-bad-tippers/?tab=comments#comment-1971638>