REFERENCE(PI_DOC_NUMBER) LIKE WISO_HEAD-DOC_NUMBER
REFERENCE(PI_DOC_NUMBER) TYPE WISO_HEAD-DOC_NUMBER
VALUE(PI_DOC_NUMBER) TYPE WISO_HEAD-DOC_NUMBER
REFERENCE(PI_DOC_NUMBER) TYPE WISO_HEAD-DOC_NUMBER OPTIONAL
REFERENCE(PI_DOC_NUMBER) TYPE WISO_HEAD-DOC_NUMBER DEFAULT SPACE