<https://powerobjects.com/tips-and-tricks/beginners-guide-how-to-perform-simple-data-validations-on-records/>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://powerobjects.com/tips-and-tricks/beginners-guide-how-to-perform-simple-data-validations-on-records/>