My customer would like to see purchase order number(s) added to the query/report below...help needed

My customer would like to see purchase order number(s) added to this report.   I'm using SQL Developer currently to create ad-hoc reports and I'm not familiar enough with the EBS data model yet to know exactly where to pull the info in from.   Help!

select /*csv*/ aps.vendor_name,

aca.check_number,

aca.amount check_total_amount,

aca.check_date,

aca.currency_code check_currency,

aia.invoice_amount,

aia.invoice_num,

aia.invoice_date,

glcc.segment1||'.'||glcc.segment2||'.'||glcc.segment3||'.'||glcc.segment4 gl_account

from ap.ap_checks_all aca,

ap.ap_invoice_payments_all aipa,