<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.audible.co.uk/pd/Crime-Thrillers/The-Hollow-Audiobook/B004EW5N6Q?ref_=sr_1_13&qid=1357815572&sr=1-13>