<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.farahat-library.com/blog/2011/07/%D8%AD%D8%B2%D9%85%D8%A9-%D9%83%D8%AA%D8%A8-%D8%A7%D9%84%D8%B1%D9%8A%D8%A7%D8%B6%D9%8A%D8%A7%D8%AA-%D9%85%D9%86-%D8%B4%D9%88%D9%85-schaums-math-book-collection/>