outer join syntax

HI, 
Regarding the syntax for outer join.....i try using this for my query...
select  ran, "pr", "followup"
from view_pr, view_followup
where ran.trialno *=* view_pr.trialno and
ran.trialno *=* view_followup.trialno;

I hope its right..but gives the error missing expression pointing at the *=*
sign...
help would be appreciated
thanx 
saf