who is starring in united states movies produced by madonna ?
select distinct var_uri where brack_open var_film rdf_type dbo_Film sep_dot var_film dbo_country dbr_United_States sep_dot var_film dbo_producer dbr_Madonna_ attr_open entertainer attr_close sep_dot var_film dbo_starring var_uri sep_dot var_uri rdf_type dbo_Person sep_dot brack_close