Transfer Order number on Intercompany AR invoice

How to identify SCO-Transfer Order number for a Intercompany AR invoice.I am trying to draft a query however encountering some issues.

SELECT DISTINCT A1.TRX_NUMBER,A1.CREATION_dATE AS INV_CREATION_DATE,
A1.INTERCOMPANY_FLAG,A1.CUSTOMER_TRX_ID,A2.PAYMENT_sCHEDULE_ID,
A2.AMOUNT_DUE_ORIGINAL,A2.AMOUNT_DUE_REMAINING,A2.STATUS,A3.TARGET_DOCUMENT_HEADER,
A4.SUPPLY_ORDER_REFERENCE_NUMBER --A5.INTERFACE_BATCH_NUMBER,--A6.HEADER_NUMBER
FROM
RA_CUSTOMER_TRX_ALL A1,AR_PAYMENT_SCHEDULES_ALL A2,FOS_FLOW_INSTANCES A3,
INV_TRANSFER_ORDER_LINES A4,DOS_SUPPLY_HEADERS A5,INV_TRANSFER_ORDER_HEADERS A6