DATA: ls_it0001 LIKE LINE OF gt_it0001,
      lv_begda  TYPE /bic/oihrc_begda.

CLEAR lv_begda.
CONCATENATE source_fields-calmonth '01' INTO lv_begda.
CONDENSE lv_begda NO-GAPS.

LOOP AT gt_it0001 INTO ls_it0001
   WHERE /bic/hrc_plans = source_fields-plans
     AND /bic/hrc_begda LE lv_begda
     AND /bic/hrc_endda GE lv_begda.

   result = ls_it0001-/bic/hrc_bukrs.
   EXIT.
ENDLOOP.
