Need to find DB link

Hi,

I have executed below SQL query and getting error due to DB link issue

/*

SQL> select * from xxbel_inv_pincode;
select * from xxbel_inv_pincode
              *
ERROR at line 1:
ORA-12154: TNS:could not resolve the connect identifier specified

SQL> spool off;

*/

Due to DB link issue above table is not executed. How to find such DB link.

Regards,

Madhu