(select
 (filter
  (bgp
    (triple ?:x <http://example/r> ?:v))
  (= ?:v
     #S(SPOCQ:DATE
        :ID COMMON-LISP:NIL
        :LEXICAL-FORM "2006-08-23"
        :YEAR 2005
        :MONTH 8
        :DAY 23
        :HOUR 0
        :MINUTE 0
        :UNIVERSAL-TIME COMMON-LISP:NIL)))
 (?:x ?:v))