subquery factoring clause [Oracle]

with
  query-name-1 as (subquery)
  [..., query-name-n as (subquery)

with 
       a as (select 42  f from dual), 
       b as (select 2*f e from a   ) 
select 
       a.f, b.e 
from 
       a cross join b;

         F          E
---------- ----------
        42         84