Supervisor Query

SELECT    papf.person_number
         ,TO_CHAR (pps.date_start
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             person_hire_date
         ,TO_CHAR (pps.actual_termination_date
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             person_termination_date
         ,TO_CHAR (paaf.effective_start_date
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             assignment_start_date
         ,TO_CHAR (paaf.effective_end_date
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             assignment_end_date
         ,TO_CHAR (pasf.effective_start_date
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             manager_start_date
         ,TO_CHAR (pasf.effective_end_date
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             manager_end_date
         ,pasf.manager_type
         ,pasf.primary_flag
         ,paaf.assignment_number
         ,papfs.person_number manager_number
         ,TO_CHAR (ppss.date_start
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             manager_hire_date
         ,TO_CHAR (ppss.actual_termination_date
                  ,'DD-Mon-YYYY'
                  ,'NLS_DATE_LANGUAGE=AMERICAN')
             manager_termination_date
FROM      per_periods_of_service ppss
         ,per_all_people_f papfs
         ,per_assignment_supervisors_f pasf
         ,per_all_people_f papf
         ,per_all_assignments_m paaf
         ,per_periods_of_service pps
WHERE         ppss.person_id(+) = papfs.person_id
          AND pasf.effective_start_date BETWEEN papfs.effective_start_date(+) AND papfs.effective_end_date(+)
          AND papfs.person_id(+) = pasf.manager_id
          AND paaf.effective_start_date BETWEEN pasf.effective_start_date(+) AND pasf.effective_end_date(+)
          AND pasf.assignment_id(+) = paaf.assignment_id
          AND papf.person_number = NVL (:p_person_number, papf.person_number)
          AND pps.date_start BETWEEN papf.effective_start_date AND papf.effective_end_date
          AND papf.person_id = paaf.person_id
          AND paaf.effective_latest_change = 'Y'
          AND paaf.primary_assignment_flag = 'Y'
          AND paaf.primary_flag = 'Y'
          AND paaf.assignment_type = 'E'
          AND paaf.period_of_service_id = pps.period_of_service_id
ORDER BY  papf.person_number
         ,paaf.effective_start_date