<https://jasonhunterdesign.com/examples-of-3-excellent-website-opt-in-forms/#schema-nav-element-34>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://schema.org/SiteNavigationElement>
<https://jasonhunterdesign.com/examples-of-3-excellent-website-opt-in-forms/>