Error creating Streams example - ORA-01729: database link name expected

Running 11gR1.  Example from doc, "4 Single-Database Capture and Apply Example"

the database name is "11G3".  when I run the Step 3 statement below, I get the error below.  What am I doing wrong?  Thanks!

 DECLARE
  iscn  NUMBER;         -- Variable to hold instantiation SCN value
BEGIN
  iscn := DBMS_FLASHBACK.GET_SYSTEM_CHANGE_NUMBER();
  DBMS_APPLY_ADM.SET_TABLE_INSTANTIATION_SCN(
    source_object_name    => 'hr.employees',
    source_database_name  => 11G3,
    instantiation_scn     => iscn);
END;
/

Error at line 1

ORA-01729: database link name expected

ORA-06512: at "SYS.DBMS_LOGREP_UTIL", line 742

ORA-06512: at "SYS.DBMS_APPLY_ADM", line 726

ORA-06512: at line 5

Error at line 1

ORA-01729: database link name expected