Função Oracle NEXT DAY

SELECT NEXT_DAY(TO_DATE('01/07/2017', 'DD/MM/YY'), 'SUNDAY') AS prox_sabado,
       NEXT_DAY(TO_DATE('29/06/2017', 'DD/MM/YY'), 'SAT') AS prox_quinta
  FROM dual;

SUNDAY  - SUN
MONDAY  - MON
TUESDAY  - TUE
WEDNESDAY- WED
THURSDAY - THU
FRIDAY  - FRI
SATURDAY - SAT