<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<http://soso.gr/tag/%CE%BA%CF%81%CE%B5%CE%B2%CE%B1%CF%84%CE%B9%CE%B1-%CE%B4%CE%B9%CF%80%CE%BB%CE%B1/>