Hi, 

I am using odoo14 and have set up an item as a subcontracted BOM with replenish on order and Buy.

This creates a PO with receipts in as well as the resupply/ delivery to the vendor/ subcontractor. the problem is that it does not show the related PO on the delivery. 

the source document displays the related receipt in that's linked to the PO. 

I need to be able to display the PO on number on the delivery to the subcontractor. 

So if i created a new field in studio is there a way i can get the source document (origin) and then pull in the source/origin of that?