<https://www.mindbounce.com/trivia/when-youre-on-cloud-nine-type-of-cloud-are-you-on/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://www.mindbounce.com/trivia/when-youre-on-cloud-nine-type-of-cloud-are-you-on/?answer=1>