# PEPPOL-EN16931-R100

Source: https://xmlvalid.com/rules/PEPPOL-EN16931-R100

> Only one invoiced object is allowed pr line

- Level: error
- Rule sets: Peppol BIS Billing 3.0 rules 3.0.21
- Context: `cac:InvoiceLine | cac:CreditNoteLine`
- Test: `(count(cac:DocumentReference) <= 1)`

## Why it fails

- An invoice line has more than one `cac:DocumentReference`.

## How to fix it

- A line can name one invoiced object (BT-128). Put other references on the line in its note (BT-127), or at document level.

Validate a document against these rules: https://xmlvalid.com/validate