(ask
 (filter
  (join
   (bgp
     (triple #S(SPOCQ:BLANK-NODE :ID COMMON-LISP:NIL :LABEL "who")
             <http://xmlns.com/foaf/0.1/homepage> ?::homepage))
   (bgp
     (triple #S(SPOCQ:BLANK-NODE :ID COMMON-LISP:NIL :LABEL "who")
             <http://xmlns.com/foaf/0.1/schoolHomepage> ?::schoolPage)))
  (regex ?::homepage "^http://example.org/")))