# UBL-SR-54

Source: https://xmlvalid.com/rules/UBL-SR-54

> An Invoice shall contain maximum one Payment Card account (BG-18).

- Level: error
- Rule sets: EN 16931 rules (UBL) 1.3.17, EN 16931 rules 1.3.16 (UBL), EXTENDED-CTC-FR rules (UBL) 1.4.0.04
- Context: `/ubl:Invoice | /cn:CreditNote`
- Test: `count(cac:PaymentMeans/cac:CardAccount) <= 1`

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