<http://schema.org/query-input>
"required name=search_term_string"^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.audible.com/pd/Bios-Memoirs/The-Madness-of-Mary-Lincoln-Audiobook/B00AKFT6HS?ref_=det_sim_narr_1>