<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<http://soso.gr/tag/hm-%CF%80%CE%B1%CE%B9%CE%B4%CE%B9%CE%BA%CE%B1-%CF%81%CE%BF%CF%85%CF%87%CE%B1/>