Get backed Purchase Requisition from Purchase Order REST API

Summary:

We are trying to find backed Requisitions from Purchase Orders, but I have found that the Get all purchase orders REST API is not showing this information; Get One Purchase Order does not show it either. Does any body know what is the right REST API to get this information?

Content (please ensure you mask any confidential information):

This is the response from the Get all purchase orders, why it has a lot information and not the Requisition that originated it?

{

    "items": [

        {

            "POHeaderId": 100000019476400,

            "OrderNumber": "1000112",

            "SoldToLegalEntityId": 204,

            "SoldToLegalEntity": "Vision Operations",

            "CreationDate": "2009-07-27T11:40:15.292+00:00",

            "StatusCode": "INCOMPLETE",

            "Status": "Incomplete",

            "ProcurementBUId": 204,

            "ProcurementBU": "Vision Operations",