How to get the child and parent relationship of invoices

Hi Team,

I am working oracle payables report of in  R12. 

In the report , i am showing invoice number, amount , dates,line data and distribution data.

Additionally   I also need to show the child records of the standard invoice like  TDS invoices, RTN invoices with their respective amounts.

Here  i have  build a subquery which calculates  RTN amount, RTN invoices of the standard invoice.

One of the sample subquery from my report :

          (select NVL(SUM(aia.invoice_amount),0)

           from ap_invoices_all aia,ap_invoice_lines_all aill,ap_invoice_distributions_all aida --,ap_suppliers aps

           where aia.attribute1 =ai.invoice_id  -- standard invoice id