<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.audible.com/pd/Romance/How-a-Cowboy-Stole-Her-Heart-Audiobook/B00BWUA6ZQ/ref=pd_rsp_tl_rd_4>