Check in Table EKBE and BKPF.
When you pass the PO number in EKBE-EBELN,Get
Material Document : EKBE-BELNR
& Reference Doc.: EKBE-LFBNR.
Pass, EKBE-LFBNR to table BKPF-XBLNR to Get accounting documents
You can also create a quick query Join the tables EKBE and BKPF.
