<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<https://celiac.org/page/2/?option=com_content&view=article&id=29%3Aceliac-disease-foundations-mission&catid=10%3Aabout-cdf&Itemid=54>