The following two reference types can be used for QR-bills with a structured reference:
QR reference: Swiss standard for payment parts with reference. The QR reference corresponds in structure to the ISR reference (26 numeric characters followed by a check digit). This can only be used in combination with a QR-IBAN.
Creditor Reference: International standard for payment parts with reference. Creditor Reference according to ISO 11649 standard. It can contain 5-25 characters. This can only be used in combination with an IBAN.