Live ORACLE

DECLARE
 emp       EMPLOYEE_TYP;
 emp_ref   REF EMPLOYEE_TYP;
 emp_name  VARCHAR2(50);
BEGIN
 SELECT Ref(e)
 INTO   emp_ref
 FROM   employee_tab e
 WHERE  e.employee_id = 370;
 -- the following assignment raises an error, not allowed in PL/SQL
 -- emp_name := emp_ref.first_name || ' ' || emp_ref.last_name;
 -- emp := DEREF(emp_ref); not allowed, cannot use DEREF in procedural statements
 SELECT Deref(emp_ref)
 INTO   emp
 FROM   dual; -- use dummy table DUAL
 emp_name := emp.first_name
             ||' '
             ||emp.last_name;
 dbms_output.Put_line(emp_name);
END;
/  

Using DEREF in a SELECT INTO Statement