SQL for FK/PK outside owning schemas

Question

I am stuck on a query design where our app is supposed to have all self contained schemas. Over the course of many years, some tables are referencing or parents to other tables in other scheamas.
What I am looking for is a query that will dertermine what tables reference tables outside of there own schemas.
example: table A.X references B.Y would be a candidate however, A.X references A.Y is OK.
Our version is 9iR2

Answer 1

This is what I came up with and it seems to work fine. May not be how most would have written it, but I just needed it to work.
/* any ri outside entered schema */
select a.owner,
       a.table_name as PARENT,
       b.owner,
       b.table_name as CHILD
from dba_constraints a, dba_constraints b
  where a.owner  = 'USER'
    and a.owner <> b.owner
  and a.constraint_type = 'P'
  and (a.constraint_name = b.r_constraint_name and
       a.owner = b.r_owner)
union all
select a.owner,
       a.table_name as PARENT,
       b.owner,
       b.table_name as CHILD
from dba_constraints a, dba_constraints b
  where b.owner = 'USER'
    and a.owner <> b.owner
  and b.constraint_type = 'R'
  and (a.constraint_name = b.r_constraint_name and
       a.owner = b.r_owner);