Source of User Defined functions.

Hello,

  I have a questions regarding the location of source code of user defined functions in Postgres. I used the following query to get all function names but I
  do not see the source code of the user defined functions. In the 'prosrc' column, data is available for trigger functions only. Is there any other table/column where function source code can be found?

SELECT p.proname, p.pronargs, t.typname,p.proowner, p.prosrc
  FROM pg_proc p, pg_language l, pg_type t
  WHERE p.prolang = l.oid
    and p.prorettype = t.oid
    and l.lanname in ('sql', 'plpgsql'  )
    and proowner = 964227
  ORDER BY proname;


  Thanks much
  Saii