SQL> CONNECT SYSTEM/xxxxx@xxx
Connected.

SQL> CREATE ROLE ROLE_ADMIN_REF2ALL;
Role created.

SQL> GRANT REFERENCES TO ROLE_ADMIN_REF2ALL;
GRANT REFERENCES TO ROLE_ADMIN_REF2ALL
      *
ERROR at line 1:
ORA-01919: role 'REFERENCES' does not exist

SQL> grant references on t to r;
grant references on t to r
*
ERROR at line 1:
ORA-01931: cannot grant REFERENCES to a role

ORA-01931: cannot grant %s to a role
 *Cause:  UNLIMITED TABLESPACE, REFERENCES, INDEX, SYSDBA or SYSOPER
          privilege cannot be granted to a role.
 *Action: Grant privilege directly to the user.

SQL> drop table parent;

Table dropped.

 SQL> create table parent (a int primary key);

Table created.
 

SQL> create table child (a int,b int, constraint fk foreign key (a) references parent (a));

Table created.

SQL> show user
USER is "BABU"
SQL>
SQL> conn sys as sysdba
Enter password:
Connected.
SQL>

SQL> drop role ref;

Role dropped.

SQL>
SQL>
SQL> create role ref;

Role created.

 
SQL> grant references on babu.child to ref;

Grant succeeded.

SQL> grant ref to ram;

Grant succeeded.

SQL> select * from v$version where rownum =1 ;

BANNER
----------------------------------------------------------------
Oracle Database 10g Express Edition Release 10.2.0.1.0 - Product

SYS> grant references on michel.t to r;

Grant succeeded.

SYS> revoke references on michel.t from r;
revoke references on michel.t from r
*
ERROR at line 1:
ORA-01927: cannot REVOKE privileges you did not grant

SYS> select * from dba_tab_privs where table_name='T' and owner='MICHEL';

no rows selected