<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.nederlandsfotomuseum.nl/index.php?option=com_nfm_collection&sub=result&Itemid=153&method=extra&met_beeld=1&vervaardiger=Behrend,%20Katharina>