Instead of the somewhat ambiguous OUTER JOIN clause, it is simpler to include the + token next to the table which is sparser when compared to the main driver table.
-- Example: Show all students, and the team they signed up
-- for, where belonging to a team is not mandatory.
select t1.last_name, t2.team_label
from students t1, teams t2
where t1.team_id = (+) t2.team_id