Referring to derived column name in a RECORD

Hi folks,

I know I'm doing something wrong here but cannot make it work no matter how
many/few quotes I use<g>

I'm trying to reference a column in a RECORD which is not a column name but
a derived column.
Any suggestions???

Example code below to highlight the problem:

DECLARE

r_app RECORD ;

BEGIN

FOR r_app IN
SELECT to_char( created_timestamp, 'DDMMYY' ) AS "joined_on",
last_name,
first_name
FROM customer
WHERE cust_id = 123
LOOP

r_app.last_name ; -- Easy to referenece this value but...
r_app.joined_on ; -- HOW do I reference this value?...this does not work

.......