<https://englishteachersite.com/lets-let-or-letted-which-is-the-correct-past-tense-of-let/#webpage>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://englishteachersite.com/lets-let-or-letted-which-is-the-correct-past-tense-of-let/>