Functions return a select in a table, which data type I must use? (Brazilian User)

Hello, friends.

If anybody can help, how can I do a FUNCTION return a result from a 
SELECT in a table in PostgreSQL?
My Problem is the RETURN TYPE from a FUNCTION, I don´t know what I have 
to use to return the data as a select result.

Example:
----------------

DROP FUNCTION ACADEMICO.teste(int4);

CREATE FUNCTION ACADEMICO.teste(int4)
RETURNS ?????
AS
'   select cod_aluno, nome, cpf from ACADEMICO.TB_alunos

'
LANGUAGE 'SQL';
----------------------------------

Thanks in Advance


André Toscano
(Brazilian user)